# Thread: Derivative laws vs. definition of derivatives

1. ## Derivative laws vs. definition of derivatives

I'm working an extra credit assignment for my class where we're supposed to end up with different answers for the derivative by using the definition of a derivative (f'(x) = lim(f(x+h) - f(x)/h) and using the derivative laws, in this case the law for the derivative of a constant. I have the two different answers, I just don't understand why they are different. Is there a difference between these two approaches? Thanks.

2. Originally Posted by hs764
I'm working an extra credit assignment for my class where we're supposed to end up with different answers for the derivative by using the definition of a derivative (f'(x) = lim(f(x+h) - f(x)/h) and using the derivative laws, in this case the law for the derivative of a constant. I have the two different answers, I just don't understand why they are different. Is there a difference between these two approaches? Thanks.
What two different answers did you get and how did you derive them?