True or false: trig identities

Exercise and reference answers

Questions

1. Statement is true

   Yes

   Statement

   Sine is odd, so sin(-x) equals -sin x.

2. Statement is true

   No

   Statement

   Cosine is odd, so cos(-x) equals -cos x.

3. Statement is true

   Yes

   Statement

   The period of tangent is pi, not 2 pi.

4. Statement is true

   No

   Statement

   A half-angle formula always takes the positive root.

5. Statement is true

   Yes

   Statement

   sin^2 x + cos^2 x = 1 for every x in the domain.

6. Statement is true

   No

   Statement

   cos(2x) can be written as 2 cos^2 x + 1.

7. Statement is true

   Yes

   Statement

   A calculator returns sine angles only in quadrants I and IV.

Instructions

Tap true or false for each statement.

Explanation