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