# prove f(x) is constant

• January 22nd 2009, 08:56 AM
jlmills5
prove f(x) is constant
Can someone explain to me where the (-1/x^2) comes from in step 2 and why?
It is in the attached image.
Thanks for any input.
• January 22nd 2009, 09:05 AM
Plato
Quote:

Originally Posted by jlmills5
Can someone explain to me where the (-1/x^2) comes from in step 2 and why? It is in the attached image.

Using the chain rule the factor $\frac {-1}{x^2}$ is the derivative of $\frac {1}{x}$.
• January 22nd 2009, 09:13 AM
jlmills5
of course. thank you.