Calculation method:

{ e^(-x)} ' = e^(-x)*(-x)' = e^(-x)*(- 1)= -e^(-x)

In this problem, -x can be regarded as u, that is:

{ e^u }′= e^u * u′= e^(-x)*(-x)′= e^(-x)*(- 1)=-e^(-x)。 Derivation of compound function of extended data, chain rule;

If h(a)=f[g(x)], then h'(a)=f'[g(x)]g'(x).

The chain rule is described in words, that is, "the derivative of a compound function composed of two functions is equal to the derivative of the internal function value substituted into the external function value and multiplied by the derivative of the internal function value."

Commonly used derivative formula:

1.y=c(c is a constant) y'=0

2.y=x^n y'=nx^(n- 1

3.y=a^x y'=a^xlna,y=e^x y'=e^x

4.y=logax y'=logae/x，y=lnx y'= 1/x