I'm having trouble showing the following:(adsbygoogle = window.adsbygoogle || []).push({});

lim [f(ax)-f(bx)]/x = f'(0)(a-b)

x→0

I feel like this should be really easy, but am I missing something? I tried to use the definition of the derivative, but I know I can't just say f(ax)-f(bx) = (a-b)f(x).

Any ideas?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Seemingly Simple Derivative (as a limit) Problem

**Physics Forums | Science Articles, Homework Help, Discussion**