### All Precalculus Resources

## Example Questions

### Example Question #1 : Use Odd Even Identities

Which of the following statements is false?

**Possible Answers:**

**Correct answer:**

Explanation:

Of the six trigonometric functions, four are odd, meaning . These four are:

- sin x
- tan x
- cot x
- csc x

That leaves two functions which are even, which means that . These are:

- cos x
- sec x

Of the aforementioned, only is incorrect, since secant is an even function, which implies that

### Example Question #2 : Use Odd Even Identities

Find the value of .

**Possible Answers:**

**Correct answer:**

Explanation:

Rewrite by odd and even identities.

Use the difference identity of sine, and choose the special angles 45 and 30, since their difference equals to 15.

### Example Question #3 : Use Odd Even Identities

Simplify:

**Possible Answers:**

**Correct answer:**

Explanation:

Write the even and odd identities for sine and cosine.

Rewrite the expression and evaluate.

### Example Question #4 : Use Odd Even Identities

Simplify:

**Possible Answers:**

**Correct answer:**

Explanation:

In order to simplify , rewrite the expression after applying the rule of odd-even identities for the secant function.