1.3 Trigonometric Functions - Calculus Volume 1 | OpenStax (2024)

Learning Objectives

  • 1.3.1Convert angle measures between degrees and radians.
  • 1.3.2Recognize the triangular and circular definitions of the basic trigonometric functions.
  • 1.3.3Write the basic trigonometric identities.
  • 1.3.4Identify the graphs and periods of the trigonometric functions.
  • 1.3.5Describe the shift of a sine or cosine graph from the equation of the function.

Trigonometric functions are used to model many phenomena, including sound waves, vibrations of strings, alternating electrical current, and the motion of pendulums. In fact, almost any repetitive, or cyclical, motion can be modeled by some combination of trigonometric functions. In this section, we define the six basic trigonometric functions and look at some of the main identities involving these functions.

Radian Measure

To use trigonometric functions, we first must understand how to measure the angles. Although we can use both radians and degrees, radians are a more natural measurement because they are related directly to the unit circle, a circle with radius 1. The radian measure of an angle is defined as follows. Given an angle θ,θ, let ss be the length of the corresponding arc on the unit circle (Figure 1.30). We say the angle corresponding to the arc of length 1 has radian measure 1.

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Figure 1.30 The radian measure of an angle θθ is the arc length ss of the associated arc on the unit circle.

Since an angle of 360°360° corresponds to the circumference of a circle, or an arc of length 2π,2π, we conclude that an angle with a degree measure of 360°360° has a radian measure of 2π.2π. Similarly, we see that 180°180° is equivalent to ππ radians. Table 1.8 shows the relationship between common degree and radian values.

DegreesRadiansDegreesRadians
001202π/32π/3
30π/6π/61353π/43π/4
45π/4π/41505π/65π/6
60π/3π/3180ππ
90π/2π/2

Table 1.8 Common Angles Expressed in Degrees and Radians

Example 1.22

Converting between Radians and Degrees

  1. Express 225°225° using radians.
  2. Express 5π/35π/3 rad using degrees.

Solution

Use the fact that 180°180° is equivalent to ππ radians as a conversion factor: 1=πrad180°=180°πrad.1=πrad180°=180°πrad.

  1. 225°=225°·π180°=5π4225°=225°·π180°=5π4 rad
  2. 5π35π3 rad = 5π3·180°π=300°5π3·180°π=300°

Checkpoint 1.17

Express 210°210° using radians. Express 11π/611π/6 rad using degrees.

The Six Basic Trigonometric Functions

Trigonometric functions allow us to use angle measures, in radians or degrees, to find the coordinates of a point on any circle—not only on a unit circle—or to find an angle given a point on a circle. They also define the relationship among the sides and angles of a triangle.

To define the trigonometric functions, first consider the unit circle centered at the origin and a point P=(x,y)P=(x,y) on the unit circle. Let θθ be an angle with an initial side that lies along the positive xx-axis and with a terminal side that is the line segment OP.OP. An angle in this position is said to be in standard position (Figure 1.31). We can then define the values of the six trigonometric functions for θθ in terms of the coordinates xx and y.y.

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Figure 1.31 The angle θθ is in standard position. The values of the trigonometric functions for θθ are defined in terms of the coordinates xx and y.y.

Definition

Let P=(x,y)P=(x,y) be a point on the unit circle centered at the origin O.O. Let θθ be an angle with an initial side along the positive xx-axis and a terminal side given by the line segment OP.OP. The trigonometric functions are then defined as

sinθ=ycscθ=1ycosθ=xsecθ=1xtanθ=yxcotθ=xysinθ=ycscθ=1ycosθ=xsecθ=1xtanθ=yxcotθ=xy

(1.9)

If x=0,secθx=0,secθ and tanθtanθ are undefined. If y=0,y=0, then cotθcotθ and cscθcscθ are undefined.

We can see that for a point P=(x,y)P=(x,y) on a circle of radius rr with a corresponding angle θ,θ, the coordinates xx and yy satisfy

cosθ=xrx=rcosθcosθ=xrx=rcosθ

sinθ=yry=rsinθ.sinθ=yry=rsinθ.

The values of the other trigonometric functions can be expressed in terms of x,y,x,y, and rr (Figure 1.32).

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Figure 1.32 For a point P=(x,y)P=(x,y) on a circle of radius r,r, the coordinates xx and yy satisfy x=rcosθx=rcosθ and y=rsinθ.y=rsinθ.

Table 1.9 shows the values of sine and cosine at the major angles in the first quadrant. From this table, we can determine the values of sine and cosine at the corresponding angles in the other quadrants. The values of the other trigonometric functions are calculated easily from the values of sinθsinθ and cosθ.cosθ.

θθsinθsinθcosθcosθ
000011
π6π612123232
π4π422222222
π3π332321212
π2π21100

Table 1.9 Values of sin θ sin θ and cos θ cos θ at Major Angles θ θ in the First Quadrant

Example 1.23

Evaluating Trigonometric Functions

Evaluate each of the following expressions.

  1. sin(2π3)sin(2π3)
  2. cos(5π6)cos(5π6)
  3. tan(15π4)tan(15π4)

Solution

  1. On the unit circle, the angle θ=2π3θ=2π3 corresponds to the point (12,32).(12,32). Therefore, sin(2π3)=y=32.sin(2π3)=y=32.
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  2. An angle θ=5π6θ=5π6 corresponds to a revolution in the negative direction, as shown. Therefore, cos(5π6)=x=32.cos(5π6)=x=32.
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  3. An angle θ=15π4=2π+7π4.θ=15π4=2π+7π4. Therefore, this angle corresponds to more than one revolution, as shown. Knowing the fact that an angle of 7π47π4 corresponds to the point (22,22),(22,22), we can conclude that tan(15π4)=yx=−1.tan(15π4)=yx=−1.
    1.3 Trigonometric Functions - Calculus Volume 1 | OpenStax (6)

Checkpoint 1.18

Evaluate cos(3π/4)cos(3π/4) and sin(π/6).sin(π/6).

As mentioned earlier, the ratios of the side lengths of a right triangle can be expressed in terms of the trigonometric functions evaluated at either of the acute angles of the triangle. Let θθ be one of the acute angles. Let AA be the length of the adjacent leg, OO be the length of the opposite leg, and HH be the length of the hypotenuse. By inscribing the triangle into a circle of radius H,H, as shown in Figure 1.33, we see that A,H,A,H, and OO satisfy the following relationships with θ:θ:

sinθ=OHcscθ=HOcosθ=AHsecθ=HAtanθ=OAcotθ=AOsinθ=OHcscθ=HOcosθ=AHsecθ=HAtanθ=OAcotθ=AO

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Figure 1.33 By inscribing a right triangle in a circle, we can express the ratios of the side lengths in terms of the trigonometric functions evaluated at θ.θ.

Example 1.24

Constructing a Wooden Ramp

A wooden ramp is to be built with one end on the ground and the other end at the top of a short staircase. If the top of the staircase is 44 ft from the ground and the angle between the ground and the ramp is to be 10°,10°, how long does the ramp need to be?

Solution

Let xx denote the length of the ramp. In the following image, we see that xx needs to satisfy the equation sin(10°)=4/x.sin(10°)=4/x. Solving this equation for x,x, we see that x=4/sin(10°)23.035x=4/sin(10°)23.035 ft.

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Checkpoint 1.19

A house painter wants to lean a 2020-ft ladder against a house. If the angle between the base of the ladder and the ground is to be 60°,60°, how far from the house should she place the base of the ladder?

Trigonometric Identities

A trigonometric identity is an equation involving trigonometric functions that is true for all angles θθ for which the functions are defined. We can use the identities to help us solve or simplify equations. The main trigonometric identities are listed next.

Rule: Trigonometric Identities

Reciprocal identities

tanθ=sinθcosθcotθ=cosθsinθcscθ=1sinθsecθ=1cosθtanθ=sinθcosθcotθ=cosθsinθcscθ=1sinθsecθ=1cosθ

Pythagorean identities

sin2θ+cos2θ=11+tan2θ=sec2θ1+cot2θ=csc2θsin2θ+cos2θ=11+tan2θ=sec2θ1+cot2θ=csc2θ

Addition and subtraction formulas

sin(α±β)=sinαcosβ±cosαsinβsin(α±β)=sinαcosβ±cosαsinβ

cos(α±β)=cosαcosβsinαsinβcos(α±β)=cosαcosβsinαsinβ

Double-angle formulas

sin(2θ)=2sinθcosθsin(2θ)=2sinθcosθ

cos(2θ)=2cos2θ1=12sin2θ=cos2θsin2θcos(2θ)=2cos2θ1=12sin2θ=cos2θsin2θ

Example 1.25

Solving Trigonometric Equations

For each of the following equations, use a trigonometric identity to find all solutions.

  1. 1+cos(2θ)=cosθ1+cos(2θ)=cosθ
  2. sin(2θ)=tanθsin(2θ)=tanθ

Solution

  1. Using the double-angle formula for cos(2θ),cos(2θ), we see that θθ is a solution of

    1+cos(2θ)=cosθ1+cos(2θ)=cosθ


    if and only if

    1+2cos2θ1=cosθ,1+2cos2θ1=cosθ,


    which is true if and only if

    2cos2θcosθ=0.2cos2θcosθ=0.


    To solve this equation, it is important to note that we need to factor the left-hand side and not divide both sides of the equation by cosθ.cosθ. The problem with dividing by cosθcosθ is that it is possible that cosθcosθ is zero. In fact, if we did divide both sides of the equation by cosθ,cosθ, we would miss some of the solutions of the original equation. Factoring the left-hand side of the equation, we see that θθ is a solution of this equation if and only if

    cosθ(2cosθ1)=0.cosθ(2cosθ1)=0.


    Since cosθ=0cosθ=0 when

    θ=π2,π2±π,π2±2π,…,θ=π2,π2±π,π2±2π,…,


    and cosθ=1/2cosθ=1/2 when

    θ=π3,π3±2π,…orθ=π3,π3±2π,…,θ=π3,π3±2π,…orθ=π3,π3±2π,…,


    we conclude that the set of solutions to this equation is

    θ=π2+nπ,θ=π3+2nπ,andθ=π3+2nπ,n=0,±1,±2,.θ=π2+nπ,θ=π3+2nπ,andθ=π3+2nπ,n=0,±1,±2,.

  2. Using the double-angle formula for sin(2θ)sin(2θ) and the reciprocal identity for tan(θ),tan(θ), the equation can be written as

    2sinθcosθ=sinθcosθ.2sinθcosθ=sinθcosθ.


    To solve this equation, we multiply both sides by cosθcosθ to eliminate the denominator, and say that if θθ satisfies this equation, then θθ satisfies the equation

    2sinθcos2θsinθ=0.2sinθcos2θsinθ=0.


    However, we need to be a little careful here. Even if θθ satisfies this new equation, it may not satisfy the original equation because, to satisfy the original equation, we would need to be able to divide both sides of the equation by cosθ.cosθ. However, if cosθ=0,cosθ=0, we cannot divide both sides of the equation by cosθ.cosθ. Therefore, it is possible that we may arrive at extraneous solutions. So, at the end, it is important to check for extraneous solutions. Returning to the equation, it is important that we factor sinθsinθ out of both terms on the left-hand side instead of dividing both sides of the equation by sinθ.sinθ. Factoring the left-hand side of the equation, we can rewrite this equation as

    sinθ(2cos2θ1)=0.sinθ(2cos2θ1)=0.


    Therefore, the solutions are given by the angles θθ such that sinθ=0sinθ=0 or cos2θ=1/2.cos2θ=1/2. The solutions of the first equation are θ=0,±π,±2π,….θ=0,±π,±2π,…. The solutions of the second equation are θ=π/4,(π/4)±(π/2),(π/4)±π,….θ=π/4,(π/4)±(π/2),(π/4)±π,…. After checking for extraneous solutions, the set of solutions to the equation is

    θ=nπandθ=π4+nπ2,n=0,±1,±2,.θ=nπandθ=π4+nπ2,n=0,±1,±2,.

Checkpoint 1.20

Find all solutions to the equation cos(2θ)=sinθ.cos(2θ)=sinθ.

Example 1.26

Proving a Trigonometric Identity

Prove the trigonometric identity 1+tan2θ=sec2θ.1+tan2θ=sec2θ.

Solution

We start with the identity

sin 2 θ + cos 2 θ = 1 . sin 2 θ + cos 2 θ = 1 .

Dividing both sides of this equation by cos2θ,cos2θ, we obtain

sin 2 θ cos 2 θ + 1 = 1 cos 2 θ . sin 2 θ cos 2 θ + 1 = 1 cos 2 θ .

Since sinθ/cosθ=tanθsinθ/cosθ=tanθ and 1/cosθ=secθ,1/cosθ=secθ, we conclude that

tan 2 θ + 1 = sec 2 θ . tan 2 θ + 1 = sec 2 θ .

Checkpoint 1.21

Prove the trigonometric identity 1+cot2θ=csc2θ.1+cot2θ=csc2θ.

Graphs and Periods of the Trigonometric Functions

We have seen that as we travel around the unit circle, the values of the trigonometric functions repeat. We can see this pattern in the graphs of the functions. Let P=(x,y)P=(x,y) be a point on the unit circle and let θθ be the corresponding angle .. Since the angle θθ and θ+2πθ+2π correspond to the same point P,P, the values of the trigonometric functions at θθ and at θ+2πθ+2π are the same. Consequently, the trigonometric functions are periodic functions. The period of a function ff is defined to be the smallest positive value pp such that f(x+p)=f(x)f(x+p)=f(x) for all values xx in the domain of f.f. The sine, cosine, secant, and cosecant functions have a period of 2π.2π. Since the tangent and cotangent functions repeat on an interval of length π,π, their period is ππ (Figure 1.34).

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Figure 1.34 The six trigonometric functions are periodic.

Just as with algebraic functions, we can apply transformations to trigonometric functions. In particular, consider the following function:

f(x)=Acos(B(xα))+C.f(x)=Acos(B(xα))+C.

(1.10)

In Figure 1.35, the constant αα causes a horizontal or phase shift. The factor BB changes the period. This transformed sine function will have a period 2π/|B|.2π/|B|. The factor AA results in a vertical stretch by a factor of |A|.|A|. We say |A||A| is the “amplitude of f.f.” The constant CC causes a vertical shift.

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Figure 1.35 A graph of a general cosine function.

Notice in Figure 1.34 that the graph of y=cosxy=cosx is the graph of y=sinxy=sinx shifted to the left π/2π/2 units. Therefore, we can write cosx=sin(x+π/2).cosx=sin(x+π/2). Similarly, we can view the graph of y=sinxy=sinx as the graph of y=cosxy=cosx shifted right π/2π/2 units, and state that sinx=cos(xπ/2).sinx=cos(xπ/2).

A shifted sine curve arises naturally when graphing the number of hours of daylight in a given location as a function of the day of the year. For example, suppose a city reports that June 21 is the longest day of the year with 15.715.7 hours and December 21 is the shortest day of the year with 8.38.3 hours. It can be shown that the function

h(t)=3.7sin(2π365(t80.5))+12h(t)=3.7sin(2π365(t80.5))+12

is a model for the number of hours of daylight hh as a function of day of the year tt (Figure 1.36).

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Figure 1.36 The hours of daylight as a function of day of the year can be modeled by a shifted sine curve.

Example 1.27

Sketching the Graph of a Transformed Sine Curve

Sketch a graph of f(x)=3sin(2(xπ4))+1.f(x)=3sin(2(xπ4))+1.

Solution

This graph is a horizontal compression by a factor of 2, a phase shift to the right by π/4 units, followed by a vertical stretch by a factor of 3, and then a vertical shift by 1 unit. The period of ff is π.π.

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Checkpoint 1.22

Describe the relationship between the graph of f(x)=3sin(4x)5f(x)=3sin(4x)5 and the graph of y=sin(x).y=sin(x).

Section 1.3 Exercises

For the following exercises, convert each angle in degrees to radians. Write the answer as a multiple of π.π.

113.

240 ° 240 °

114.

15 ° 15 °

115.

−60 ° −60 °

116.

−225 ° −225 °

117.

330 ° 330 °

For the following exercises, convert each angle in radians to degrees.

118.

π 2 rad π 2 rad

119.

7 π 6 rad 7 π 6 rad

120.

11 π 2 rad 11 π 2 rad

121.

−3 π rad −3 π rad

122.

5 π 12 rad 5 π 12 rad

Evaluate the following functional values.

123.

cos ( 4 π 3 ) cos ( 4 π 3 )

124.

tan ( 19 π 4 ) tan ( 19 π 4 )

125.

sin ( 3 π 4 ) sin ( 3 π 4 )

126.

sec ( π 6 ) sec ( π 6 )

127.

sin ( π 12 ) sin ( π 12 )

128.

cos ( 5 π 12 ) cos ( 5 π 12 )

For the following exercises, consider triangle ABC, a right triangle with a right angle at C. a. Find the missing side of the triangle. b. Find the six trigonometric function values for the angle at A. Where necessary, simplify to a fraction or round to three decimal places.

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129.

a = 4 , c = 7 a = 4 , c = 7

131.

a = 85.3 , b = 125.5 a = 85.3 , b = 125.5

132.

b = 40 , c = 41 b = 40 , c = 41

133.

a = 84 , b = 13 a = 84 , b = 13

134.

b = 28 , c = 35 b = 28 , c = 35

For the following exercises, PP is a point on the unit circle. a. Find the (exact) missing coordinate value of each point and b. find the values of the six trigonometric functions for the angle θθ with a terminal side that passes through point P.P. Rationalize denominators.

135.

P ( 7 25 , y ) , y > 0 P ( 7 25 , y ) , y > 0

136.

P ( −15 17 , y ) , y < 0 P ( −15 17 , y ) , y < 0

137.

P ( x , 7 3 ) , x < 0 P ( x , 7 3 ) , x < 0

138.

P ( x , 15 4 ) , x > 0 P ( x , 15 4 ) , x > 0

For the following exercises, simplify each expression by writing it in terms of sines and cosines, then simplify. The final answer does not have to be in terms of sine and cosine only.

139.

tan 2 x + sin x csc x tan 2 x + sin x csc x

140.

sec x sin x cot x sec x sin x cot x

141.

tan 2 x sec 2 x tan 2 x sec 2 x

142.

sec x cos x sec x cos x

143.

( 1 + tan θ ) 2 2 tan θ ( 1 + tan θ ) 2 2 tan θ

144.

sin x ( csc x sin x ) sin x ( csc x sin x )

145.

cos t sin t + sin t 1 + cos t cos t sin t + sin t 1 + cos t

146.

1 + tan 2 α 1 + cot 2 α 1 + tan 2 α 1 + cot 2 α

For the following exercises, verify that each equation is an identity.

147.

tan θ cot θ csc θ = sin θ tan θ cot θ csc θ = sin θ

148.

sec 2 θ tan θ = sec θ csc θ sec 2 θ tan θ = sec θ csc θ

149.

sin t csc t + cos t sec t = 1 sin t csc t + cos t sec t = 1

150.

sin x cos x + 1 + cos x 1 sin x = 0 sin x cos x + 1 + cos x 1 sin x = 0

151.

cot γ + tan γ = sec γ csc γ cot γ + tan γ = sec γ csc γ

152.

sin 2 β + tan 2 β + cos 2 β = sec 2 β sin 2 β + tan 2 β + cos 2 β = sec 2 β

153.

1 1 sin α + 1 1 + sin α = 2 sec 2 α 1 1 sin α + 1 1 + sin α = 2 sec 2 α

154.

tan θ cot θ sin θ cos θ = sec 2 θ csc 2 θ tan θ cot θ sin θ cos θ = sec 2 θ csc 2 θ

For the following exercises, solve the trigonometric equations on the interval 0θ<2π.0θ<2π.

155.

2 sin θ 1 = 0 2 sin θ 1 = 0

156.

1 + cos θ = 1 2 1 + cos θ = 1 2

157.

2 tan 2 θ = 2 2 tan 2 θ = 2

158.

4 sin 2 θ 2 = 0 4 sin 2 θ 2 = 0

159.

3 cot θ + 1 = 0 3 cot θ + 1 = 0

160.

3 sec θ 2 3 = 0 3 sec θ 2 3 = 0

161.

2 cos θ sin θ = sin θ 2 cos θ sin θ = sin θ

162.

csc 2 θ + 2 csc θ + 1 = 0 csc 2 θ + 2 csc θ + 1 = 0

For the following exercises, each graph is of the form y=AsinBxy=AsinBx or y=AcosBx,y=AcosBx, where B>0.B>0. Write the equation of the graph.

163.

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164.

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165.

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166.

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For the following exercises, find a. the amplitude, b. the period, and c. the phase shift with direction for each function.

167.

y = sin ( x π 4 ) y = sin ( x π 4 )

168.

y = 3 cos ( 2 x + 3 ) y = 3 cos ( 2 x + 3 )

169.

y = −1 2 sin ( 1 4 x ) y = −1 2 sin ( 1 4 x )

170.

y = 2 cos ( x π 3 ) y = 2 cos ( x π 3 )

171.

y = −3 sin ( π x + 2 ) y = −3 sin ( π x + 2 )

172.

y = 4 cos ( 2 x π 2 ) y = 4 cos ( 2 x π 2 )

173.

[T] The diameter of a wheel rolling on the ground is 40 in. If the wheel rotates through an angle of 120°,120°, how many inches does it move? Approximate to the nearest whole inch.

174.

[T] Find the length of the arc intercepted by central angle θθ in a circle of radius r. Round to the nearest hundredth.

a. r=12.8r=12.8 cm, θ=5π6θ=5π6 rad b. r=4.378r=4.378 cm, θ=7π6θ=7π6 rad c. r=0.964r=0.964 cm, θ=50°θ=50° d. r=8.55r=8.55 cm, θ=325°θ=325°

175.

[T] As a point P moves around a circle, the measure of the angle changes. The measure of how fast the angle is changing is called angular speed, ω,ω, and is given by ω=θ/t,ω=θ/t, where θθ is in radians and t is time. Find the angular speed for the given data. Round to the nearest thousandth.

a. θ=7π4rad,t=10θ=7π4rad,t=10 sec b. θ=3π5rad,t=8θ=3π5rad,t=8 sec c. θ=2π9rad,t=1θ=2π9rad,t=1 min d. θ=23.76rad,t=14θ=23.76rad,t=14 min

176.

[T] A total of 250,000 m2 of land is needed to build a nuclear power plant. Suppose it is decided that the area on which the power plant is to be built should be circular.

  1. Find the radius of the circular land area.
  2. If the land area is to form a 45°45° sector of a circle instead of a whole circle, find the length of the curved side.

177.

[T] The area of an isosceles triangle with equal sides of length x is

1 2 x 2 sin θ , 1 2 x 2 sin θ ,

where θθ is the angle formed by the two sides. Find the area of an isosceles triangle with equal sides of length 8 in. and angle θ=5π/12θ=5π/12 rad.

178.

[T] A particle travels in a circular path at a constant angular speed ω.ω. The angular speed is modeled by the function ω=9|cos(πtπ/12)|.ω=9|cos(πtπ/12)|. Determine the angular speed at t=9t=9 sec.

179.

[T] An alternating current for outlets in a home has voltage given by the function

V ( t ) = 150 cos 368 t , V ( t ) = 150 cos 368 t ,

where V is the voltage in volts at time t in seconds.

  1. Find the period of the function and interpret its meaning.
  2. Determine the number of periods that occur when 1 sec has passed.

180.

[T] The number of hours of daylight in a northeast city is modeled by the function

N ( t ) = 12 + 3 sin [ 2 π 365 ( t 79 ) ] , N ( t ) = 12 + 3 sin [ 2 π 365 ( t 79 ) ] ,

where t is the number of days after January 1.

  1. Find the amplitude and period.
  2. Determine the number of hours of daylight on the longest day of the year.
  3. Determine the number of hours of daylight on the shortest day of the year.
  4. Determine the number of hours of daylight 90 days after January 1.
  5. Sketch the graph of the function for one period starting on January 1.

181.

[T] Suppose that T=50+10sin[π12(t8)]T=50+10sin[π12(t8)] is a mathematical model of the temperature (in degrees Fahrenheit) at t hours after midnight on a certain day of the week.

  1. Determine the amplitude and period.
  2. Find the temperature 7 hours after midnight.
  3. At what time does T=60°?T=60°?
  4. Sketch the graph of TT over 0t24.0t24.

182.

[T] The function H(t)=8sin(π6t)H(t)=8sin(π6t) models the height H (in feet) of the tide t hours after midnight. Assume that t=0t=0 is midnight.

  1. Find the amplitude and period.
  2. Graph the function over one period.
  3. What is the height of the tide at 4:30 a.m.?
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FAQs

Is Calc 1 harder than trig? ›

In general, calculus is considered to be more difficult than trigonometry due to the complexity of the concepts. However, the difficulty level can also depend on your personal strengths, interests, and previous experience with math courses.

Do you need trig for Calc 1? ›

In some sense, the prerequisite for Calculus is to have an overall comfort with algebra, geometry, and trigonometry. After all, each new topic in math builds on previous topics, which is why mastery at each stage is so important.

What is trigonometry in calculus? ›

Trigonometric functions allow us to use angle measures, in radians or degrees, to find the coordinates of a point on any circle—not only on a unit circle—or to find an angle given a point on a circle. They also define the relationship among the sides and angles of a triangle.

What are the circular functions in calculus? ›

Circular functions are another name for trigonometric functions, or sine, cosine, tangent, secant, cosecant, and cotangent. They are called circular functions because they can be used to describe the coordinates around a circle on a coordinate graph.

Why is calculus 1 so hard? ›

Calculus is widely regarded as a very hard math class, and with good reason. The concepts take you far beyond the comfortable realms of algebra and geometry that you've explored in previous courses. Calculus asks you to think in ways that are more abstract, requiring more imagination.

Is calculus 1 harder than algebra? ›

Which is generally considered more challenging, algebra or calculus? The perception of difficulty varies among individuals, but calculus is often considered more challenging due to its introduction of new concepts like limits, derivatives, and integrals, building upon the foundation laid by algebra.

Can I learn Calc without trig? ›

There's no prerequisite to learn trig first, and forcing people to learn trig-calc excites many mathophiles but is a major turn off to other students. Calculus can be taught using just basic algebra, and most students will benefit from already understanding calculus, when they are learning trigonometry.

Is trig or pre calc easier? ›

If you are more comfortable with solving algebraic equations and working with functions, you might find pre-calculus to be easier. However, if you enjoy working with spatial concepts and geometric relationships, trigonometry could be your better option.

How to pass calculus 1? ›

Don't wait to study until just before a test. Begin studying for tests on the first day of class by keeping up with assignments and readings, attending class and taking notes, and using available help regularly. Memorize theorems, rules and formulas as they appear in the course, and test yourself on them.

What grade math is trigonometry? ›

In general, trigonometry is taken as part of sophom*ore or junior year math. In addition to being offered as its own course, trigonometry is often incorporated as a unit or semester focus in other math courses.

Is calculus more like trig or algebra? ›

Yes, calculus involves quite a bit of algebra. Before learning calculus, math students should be familiar with exponential, logarithmic, and trigonometric functions, and know how to solve linear, cubic, and quadratic equations.

Is trigonometry 11th grade math? ›

So basically, trigonometry is a study of triangles, which has angles and lengths on its side. Trigonometry basics consist of sine, cosine and tangent functions. Trigonometry for class 11 contains trigonometric functions, identities to solve complex problems more simply.

What does the Soh Cah Toa stand for? ›

Students will be familiar with the mnemonic SOHCAHTOA, which explains trig formulas -- sine opposite hypotenuse, cosine adjacent hypotenuse and tangent opposite adjacent -- the formulas needed to solve the side/angle relationships of right triangles. Hope Babowice, Daily Herald, January, 2016.

What is the full meaning of sine? ›

sine. noun. ˈsīn. : a trigonometric function that for an acute angle in a right triangle is the ratio of the side opposite the angle to the hypotenuse.

What are the formulas of trigonometry? ›

sin θ = Opposite Side/Hypotenuse. cos θ = Adjacent Side/Hypotenuse. tan θ = Opposite Side/Adjacent Side. sec θ = Hypotenuse/Adjacent Side.

Which is harder, trig or pre-calc? ›

If you are more comfortable with solving algebraic equations and working with functions, you might find pre-calculus to be easier. However, if you enjoy working with spatial concepts and geometric relationships, trigonometry could be your better option.

Is trigonometry the hardest math? ›

Trigonometry is one of the most challenging subjects for students to learn. Many students find themselves struggling with the concepts and principles involved in trigonometry. This can often lead to frustration and a feeling of being overwhelmed.

Is Calc 1 harder than business Calc? ›

It covers similar concepts to regular Calculus but focuses on their applications to business and economics problems, such as optimization, revenue, and cost analysis. This course often involves a lesser workload and moves at a slightly slower pace than regular Calculus.

Is Calc 1 or stats harder? ›

Some students might find Calculus harder, while others might struggle more with Statistics. It's highly personal, so talk to your teachers and peers to help you make the best decision.

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