 # Review of Trigonometric Functions

9. Let r represent the radius of a circle, θ the central angle
(measured in radians), and s the length of the arc subtended by
the angle. Use the relationship to complete the table. 10. Angular Speed A car is moving at the rate of 50 miles per
hour, and the diameter of its wheels is 2.5 feet.

(a) Find the number of revolutions per minute that the wheels
are rotating.

(b) Find the angular speed of the wheels in radians per minute.

In Exercises 11 and 12, determine all six trigonometric
functions for the angle θ In Exercises 13 and 14, determine the quadrant in which θ lies. In Exercises 15–18, evaluate the trigonometric function . In Exercises 19–22, evaluate the sine, cosine, and tangent of
each angle without using a calculator . In Exercises 23–26, use a calculator to evaluate the trigonometric
functions to four significant digits . In Exercises 27–30, find two solutions of each equation . Express
the results in radians(0≤θ<2π) Do not use a calculator. In Exercises 31–38, solve the equation for θ (0≤θ<2π) 39. Airplane Ascent An airplane leaves the runway climbing at
18° with a speed of 275 feet per second (see figure). Find the
altitude a of the plane after 1 minute. 40. Height of a Mountain In traveling across flat land, you
notice a mountain directly in front of you. Its angle of elevation
(to the peak) is 3.5° After you drive 13 miles closer to the
mountain, the angle of elevation is 9° Approximate the height
of the mountain. (not to scale)

In Exercises 41–44, determine the period and amplitude of each
function. In Exercises 45–48, find the period of the function.  Writing In Exercises 49 and 50, use a graphing utility to
graph each function f on the same set of coordinate axes for , and .Give a written description
of the change in the graph caused by changing c. In Exercises 51–62, sketch the graph of the function. Graphical Reasoning In Exercises 63 and 64, find a, b, and
c such that the graph of the function matches the graph in the
figure. 65. Think About It. Sketch the graphs of , and . In general , how are the
graphs of and related to the graph of f?

66. Think About It The model for the height h of a Ferris wheel
car is where t is measured in minutes. (The Ferris wheel has a radius
of 50 feet.) This model yields a height of 51 feet when t=0
Alter the model so that the height of the car is 1 foot when
t=0. 67. Sales Sales S, in thousands of units, of a seasonal product are
modeled by where t is the time in months (with t=1 corresponding to
January and t=12 corresponding to December). Use a graphing
utility to graph the model for S and determine the months
when sales exceed 75,000 units.

68. Investigation Two trigonometric functions f and g have a
period of 2, and their graphs intersect at x=5.35.

(a) Give one smaller and one larger positive value of x where
the functions have the same value .

(b) Determine one negative value of x where the graphs
intersect.

(c) Is it true that Give a reason for your Pattern Recognition In Exercises 69 and 70, use a graphing 