A student claims that the function f(x)=x4+kx2+1 is an even function. Which statement best describes the student's claim?

Answer 1

A student claims that the function f(x)=x^4 + kx^2 + 1 is an even function. Which statement best describes the student's claim?

The student's claim is true for all values of k.
The student's claim is only true for even values of k.
The student's claim is not true for any value of k.
The student's claim is only true for odd values of k.

Answer 2

I think the answer is the third one or fourth one but I am not sure

Answer 3

Because I substituted "x" with 1 and -1 and got
(1)=2k
(-1)= k

Answer 4

all powers of x are even, so the function is even for all k.
f(-x) = f(x) so f is even.

Answer 5

The answer is the first one for anyone who sees this. :) (well it was for me)