hello!

i was randomly searching things about functions and i was teaching myself domain and range. i understand those.

however, i don't understand even and odd functions

i understand the basic ones like x^2 |x| and cos x are even and x^3 sinx and tanx are odd..

i was wondering what these were:

f(x)= 2^x

f(x)= log base 2 x

f(x)= square root of x

and f(x)= square root of a^2 - x^2

thank you!