3. Unit Circle

Evaluate each expression.

$\(\cot\[\left\)(\(\frac{11\pi}{6}\]\right\))$

Evaluate each expression.

$\(\csc\)225\(\degree\)$

Evaluate each expression.

$\(\sec\[\left\)(\(\frac{\pi}{3}\]\right\))$

In Exercises 5–18, the unit circle has been divided into twelve equal arcs, corresponding to t-values of

0, 𝜋, 𝜋, 𝜋, 2𝜋, 5𝜋, 𝜋, 7𝜋, 4𝜋, 3𝜋, 5𝜋, 11𝜋, and 2𝜋.

6 3 2 3 6 6 3 2 3 6

Use the (x,y) coordinates in the figure to find the value of each trigonometric function at the indicated real number, t, or state that the expression is undefined.

<IMAGE>

In Exercises 11–18, continue to refer to the figure at the bottom of the previous page.

sec 3𝜋/2

In Exercises 5–18, the unit circle has been divided into twelve equal arcs, corresponding to t-values of

0, 𝜋, 𝜋, 𝜋, 2𝜋, 5𝜋, 𝜋, 7𝜋, 4𝜋, 3𝜋, 5𝜋, 11𝜋, and 2𝜋.

6 3 2 3 6 6 3 2 3 6

Use the (x,y) coordinates in the figure to find the value of each trigonometric function at the indicated real number, t, or state that the expression is undefined.

<IMAGE>

In Exercises 11–18, continue to refer to the figure at the bottom of the previous page.

sec 11𝜋/6

In Exercises 5–18, the unit circle has been divided into twelve equal arcs, corresponding to t-values of

0, 𝜋, 𝜋, 𝜋, 2𝜋, 5𝜋, 𝜋, 7𝜋, 4𝜋, 3𝜋, 5𝜋, 11𝜋, and 2𝜋.

6 3 2 3 6 6 3 2 3 6

Use the (x,y) coordinates in the figure to find the value of each trigonometric function at the indicated real number, t, or state that the expression is undefined.

<IMAGE>

In Exercises 11–18, continue to refer to the figure at the bottom of the previous page.

csc 7𝜋/6

In Exercises 25–32, the unit circle has been divided into eight equal arcs, corresponding to t-values of

0, 𝜋/4, 𝜋/2, 3𝜋/4, 𝜋, 5𝜋/4, 3𝜋/2, 7𝜋/4, and 2𝜋.

a. Use the (x,y) coordinates in the figure to find the value of the trigonometric function.

b. Use periodic properties and your answer from part (a) to find the value of the same trigonometric function at the indicated real number.

<IMAGE>

cot 𝜋/2

In Exercises 25–32, the unit circle has been divided into eight equal arcs, corresponding to t-values of

0, 𝜋, 𝜋, 3𝜋, 𝜋, 5𝜋, 3𝜋, 7𝜋, and 2𝜋.

4 2 4 4 2 4

a. Use the (x,y) coordinates in the figure to find the value of the trigonometric function.

cos 3𝜋/4

Give the exact value of each expression. See Example 5. sec 45°

Give the exact value of each expression. See Example 5. cot 45°

Give the exact value of each expression. See Example 5. csc 60°

Concept Check Work each problem. For what angles θ between 0° and 360° is cos θ = sin θ true?