Differentiate y=a^xusing first principle?

1 Answer
Feb 19, 2018

{dy}/{dx} = a^x ln(a)dydx=axln(a)

Explanation:

First, you have to know the limit

lim_{h->0} (a^h-1)/h = ln(a)

Now, for the problem.

y(x) = a^x

y'(x) = lim_{h->0} (y(x+h)-y(x))/h

= lim_{h->0} (a^(x+h) - a^x)/h

= lim_{h->0} (a^x*a^h - a^x)/h

= a^x lim_{h->0} (a^h - 1)/h

= a^x ln(a)