Question

The limit represents the derivative of some function f at some number a. State such an f and a. lim h→0 (cos(π + h) + 1)/h f(x) = cos(x), a = π
f(x) = cos(x), a = 0
f(x) = cos(x), a = π/4
f(x) = cos(x), a = π/3
f(x) = cos(x), a = π/6