How do you use the limit definition of the derivative to find the derivative of f(x)=-x+6f(x)=x+6?

1 Answer
Sep 26, 2016

f'(x)=-1

Explanation:

By definition: f'(x) = lim_"h->0" (f(x+h)-f(x))/h

In this example f(x)=-x+6

Hence: f'(x) = lim_"h->0"(-x-h+6+x-6)/h

f'(x) = lim_"h->0"(cancel(-x)-hcancel(+6)cancel(+x)cancel(-6))/h

f'(x) = lim_"h->0" -h/h =-1