If f and g are differentiable, then the derivative of f∘g is given by:
(f∘g)′=ddx[f(g(x))]=f′(g(x))g′(x)
This follows directly from the chain rule.
If f has an inverse function g, then:
g′(x)=1f′(g(x))
Derivatives of inverse functions are **reciprocal slopes**.
In implicit differentiation, you will have a dydx for each y in the original function or equation. The steps are:
If you are taking the second derivative d2ydx2, you will often substitute the expression you found for the first derivative somewhere in the process.