A function f(x) is odd, when

a-function-f-x-is-odd-when-a-f-x-f-x-b-f-x-f-x

A function f(x) is odd, when?
A. f(x) = -f(x)
B. f(x) = f(-x)
C. f(x) = -f(x)f(-x)
D. f(x) = f(x)f(-x)
Correct option is A. f(x) = -f(x)

Geometrically a function f(x) is even, if plot of the function is symmetric over y-axis. Algebraically, for any function f(x) to be even, f(x) = f(-x).

While for a function f(x) to be odd, f(x) = -f(-x).