[Study notes]
Derivation method is the chain rule of calculus in the composite function. Complex function, means that one independent variable as a function of another function. The f (x) = 3x, g (z) = z + 3, g (f (x)) is a complex function, and g (f (x)) = f (x) + 3 = 3x + 3
chain rule (chain rule): if m (x) = f (g (x)), then m '(x) = f' (g (x)) g '(x)
i.e. "two functions pooled complex function , which is equal to the derivative function inside substituting the derivative function value outside, multiplying the derivative of the function inside.
Reprinted from the original article: https://blog.csdn.net/qq_44639795/article/details/100591048