Question

lim ( cos x ) 4/x²

Answer 1

x→0,lim(cosx)^(4/x^2)

=e^lim(4(lncosx)/x^2)

因为x→0,lncosx=0,x^2=0

罗比达法则,得：

=e^lim[4(-sinx/cosx)/2x] =e^-2