How to check if derivative equation is correct? I can calculate the derivative of a function using the product rule, chain rule or quotient rule.
When I find the resulting derivative function however, I have no way to check if my answer is correct!
How can I check if the calculated derivative equation is correct? (ie I haven't made a mistake factorising, or with one of the rules).
I have a graphics calculator.
Thanks!

Many derivative problems can be done more than one way.  One way to check your work is to try them both ways and see if you get the same thing.
For example:  $y=\frac{1}{x^2}$
You can write this as $y=x^{-2}$ and use the power rule to get $y'=-2x^{-3}=\frac{-2}{x^3}$
Or you can use the quotient rule $y'=\frac{0*x^2-2*x}{{(x^2)}^2}=\frac{-2x}{x^4}=\frac{-2}{x^3}$
This is probably too simple of an example, but I hope you get the idea.
