求lim{下面(x属于0）}（1-cosx)/ln(1+x^2)的极限怎么算?

求lim{下面(x属于0）}（1-cosx)/ln(1+x^2)的极限怎么算?

lim(x→0)(1-cosx)/ln(1+x^2)
[洛必达法则]
=lim(x→0)sinx/[(2x)/(1+x^2)]
=lim(x→0)[sinx/2x]*(1+x^2)
[sinx和x是等价无穷小量]
=1/2*1
=1/2

1-cosx~1/2x^2
1/2

1/2