y=f(x)=c (c为常数)，则f'(x)=0
f(x)=x^n (n不等于0) f'(x)=nx^(n-1) (x^n表示x的n次方)
f(x)=sinx f'(x)=cosx
f(x)=cosx f'(x)=-sinx
f(x)=tanx f'(x)=sec^2x
f(x)=a^x f'(x)=a^xlna(a>0且a不等于1，x>0)
f(x)=e^x f'(x)=e^x
f(x)=logaX f'(x)=1/xlna (a>0且a不等于1，x>0)
f(x)=lnx f'(x)=1/x (x>0)
f(x)=tanx f'(x)=1/cos^2 x
f(x)=cotx f'(x)=- 1/sin^2 x
f(x)=acrsin(x) f'(x)=1/√(1-x^2)
f(x)=acrcos(x) f'(x)=-1/√(1-x^2)
f(x)=acrtan(x) f'(x)=-1/(1+x^2)
