[" Let "f(x+y)=f(x)+f(y)" for all "],[x,y in R" .Then "],[" (A) "f(x)" is an even function "],[" (B) "f(x)" is an odd function "],[" (C) "f(0)=0],[" (D) "f(n)=nf(1),n in N]

Let f:R to R such that f(x+y)+f(x-y)=2f(x)f(y) for all x,y in R . Then,

Let f(x+y) + f(x-y) = 2f(x)f(y) for x, y in R and f(0) != 0 . Then f(x) must be

Let f(x+y)=f(x)f(y) for all x and y.Then what is f'(5) equal to (where f'(x) is the derivative of f(x))?

Let f(x+y)=f(x)f(y) for all x,y in R suppose that f(3)=3,f(0)!=0 and f'(0)=11, then f'(3) is equal

Let f(x+y)= f(x)+f(y) for all x, y in R Then (A) f(x) must be continuous AA x in R (B) f(x) may be continuous AA x in R (C) f(x) must be discontinuous AA x in R (D) f(x) may be discontinuous AA x in R

Let f(x+y)+f(x-y)=2f(x)f(y)AA x,y in R and f(0)=k, then