Lesson 21 of 48
Rules of differentiation
The handful of patterns that cover almost everything.
The rules are theorems, not spells. Deriving them once from the limit definition means you can rebuild any of them on a bad day rather than misremembering one.
Do this
Differentiate a mixed set of functions with the power, product and quotient rules, then verify every one numerically against the limit definition.
The question that unlocks the next lesson
The derivative of f(x)·g(x) is…
- Af′(x)·g′(x)
- Bf′(x)·g(x) + f(x)·g′(x)
- Cf′(x) + g′(x)
- Df(x)·g′(x)