Question

The limit

lim as x approaches 1 of (x^12-1)/(x-1)

represents the derivative of some function f(x) at some number a. Find f and a.

Answer 1

derivative of top = 12 x^11
derivative of bottom = 1
so I get 12

If f = 12 x
f'(x) = 12
for any old x = a