Question

Need math help please get back to me soon

Answer 1

Answer:

Option C.

Step-by-step explanation:

By definition, a function f(x) is even if f(-x) =  f(x).

We know by definition that the function sin(x) is odd and the function cos(x) is even.

With this information we can analyze each function and find out which is even.

A. The first function is not even because 5sin(x) is an odd function.

B. The second function is not even because 2tan(x) is not an even function.

C. The third function is even, because -cos(x) and $3cos^2(3x)$ are even functions.

$f(-x) = 3cos^2(3(-x)) - cos(-x) = 3cos^2(3(x)) - cos(x) = f(x)$

D. The fourth function is not even because csc(x) is not an even function.

The correct answer is the option C.