导数定义：f'(x)=lim(h->0)[f(x+h)-f(x)]/h，lim(h→0)[f(x+h)-f(x-h)]/2h，lim(h→0)[f(x+2h)-f(x)]/2h
lim(h→0)[f(0+h)-f(0-h)]/2h=2lim(h→0)[f(0-h+2h)-f(0-h)]/2h=lim(h->0)2f'(0-h)当f'(x)在x=0处连续才有lim(h->0)2f'(0-h)=2f'(0)
扩展资料
常用导数公式：
1、y=c(c为常数) 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
5、y=sinx y'=cosx
6、y=cosx y'=-sinx
7、y=tanx y'=1/cos^2x
8、y=cotx y'=-1/sin^2x
9、y=arcsinx y'=1/√1-x^2
10、y=arccosx y'=-1/√1-x^2