If f(x) satisfies the relation f(x + y) = f(x) + f(y) ∀ x, y ∈ R. Then f(x) is
Odd Function
Even function
Both (1) and (2)
None
Even function:
If for a function f(x), f(-x) = f(x) then the function is known as even function. Even functions are symmetric about the y axis.
y = x2 y = |x| y = cos(x)
Odd function:
If for a function f(x), f(-x) = - f(x) then the function is known as odd function. Odd functions are symmetric about the origin.
y = sin(x) y = x3
NOTE: We can have functions that are neither even nor odd. Eg, y = x+1
Given, f(x + y) = f(x) + f(y)
Put x = 0, y = 0
f(0 + 0) = f(0) + f(0) ⇒ f(0) = 0
Now, replace y with (-x)
f(x - x) = f(x) + f(-x)
f(0) = f(x) + f(-x)
f(x) = -f(-x)
f(x) is odd function