For which of the following functions is f(q) = f(−q) for all values of q ?
Choose the most appropriate option.
A) f(x) = x^3 + 3	B) f(x) = −x	C) f(x) = 2x + 3	D) f(q) = −q^2 + 2	E) f(x) = 5x − 4
f(q) = f(−q)   The above is a property of an even function .   f(q) = f^(n)   f(q) = f(−q) will hold when n is an even integer .   The only case when q is even is option f(q) = −q^2 + 2   Answer f(q) = −q^2 + 2
<result>D</result>
For which of the following functions is f(q) = f(−q) for all values of q ?