3. Unit Circle

Write each function in terms of its cofunction. Assume all angles involved are acute angles. See Example 2. tan 25.4°

Use a calculator to determine whether each statement is true or false. A true statement may lead to results that differ in the last decimal place due to rounding error. cos 70° = 2 cos² 35° - 1

Suppose an arc of length s lies on the unit circle x² + y² = 1, starting at the point (1, 0) and terminating at the point (x, y). (See Figure 12, repeated below.) Use a calculator to find the approximate coordinates for (x, y) to four decimal places.

s = 2.5

<IMAGE>

Find each exact function value.

sin ( ―5π/6)

Graph each function over a one-period interval.

y = - (1/2) csc (x + π/2)

Find each exact function value. See Example 2.

tan 5π/6

Find one solution for each equation. Assume all angles involved are acute angles. See Example 3. cot(5θ + 2°) = tan(2θ + 4°)

Find two angles in the interval [0°, 360°) that satisfy each of the following. Round answers to the nearest degree. tan θ = 0.70020753