① Find the increment δ y = f (x0+δ x)-f (x0) of the function.

② Find the average change rate.

③ Seek the limit and derivative.

(2) Derivative formulas of several common functions:

① C'=0(C is a constant);

②(x^n)'=nx^(n- 1)(n∈q)；

③(sinx)' = cosx；

④(cosx)' =-sinx；

⑤(e^x)'=e^x；

⑥ (a^x)'=a^xLna

(3) Four algorithms of derivative:

①(u v)'=u' v '

②(uv)'=u'v+uv '

③(u/v)'=(u'v-uv')/ v^2

(4) Derivative of composite function

The derivative of the compound function to the independent variable is equal to the derivative of the known function to the intermediate variable, multiplied by the derivative of the intermediate variable to the independent variable, which is the so-called chain rule.