1. The problem statement, all variables and given/known data Use the definition of a derivitive to find f'(x). f(x)=1/(1-4X) 2. Relevant equations Lim as h approaches 0 [f(x+h)-f(x)]/h 3. The attempt at a solution I know that the answer is supposed to be -1/(1-4X)2 but I keep getting 4/(1-4X)2. This is what I have done so far (I hope this isn't too hard to understand): f'(x)= (1/(1-4(x+h))-(1/(1-4x)))/h = ((1-4x-(1-4(x+h)))/((1-4(x+h))(1-4x)))/h = ((1-4x-1+4x+4h)/((1-4(x+h))(1-4x)))/h *cancel the numerator values* =(4h)/((1-4(x+h))(1-4x))/h *divide by 1/h and let h=0* =4/(1-4(x-0))(1-4x) =4/(1-4X)2 What am I doing wrong?