### Home > A2C > Chapter 13 > Lesson 13.1.1 > Problem 13-5

13-5.

Decide if each of the following statements are always true, sometimes true, or never true. If a statement is always true, justify how you know; if it is sometimes true, give the exact values of that make it true; and if it is never true, explain why it is never true.

Simplify the part of the equation on the left side of the equals sign.

Does it equal the part on the right side?Always.

Use the same method as part (a).

sin(

)cos( ) Substitute values into the equations for

*x*.

Are they always equal?Always.

tan(

)Is this always true?

If not, what values ofwould make it true?