If f is defined by f (x) = x2, find f ‘ (2).
We are given with a polynomial function f(x) = x2, and we have to find whether it is derivable at x = 2 or not, so by using the formula, f ‘(c) = , we get,
f ‘(2) =
f ‘(2) =
f ‘(2) =
[using a2 - b2 = (a + b)(a - b)]
f ‘(2) = limx→2 x + 2 = 4
Hence, the function is differentiable at x = 2 and its derivative equals to 4.