设 f(0)=1 ,f'(0)= -1 求------------------ X→0时,( cosX - f(x) )÷ X =

问题描述:

设 f(0)=1 ,f'(0)= -1 求------------------ X→0时,( cosX - f(x) )÷ X =

lim(X→0)[cosx-f(x)]/x
=lim(X→0)[-sinx-f'(x)]
=-f'(0)
=1