运用极限的运算性质
lim(x→0)[sinx(e^x-1)/(1-cosx)+ln(1+x)/tanx]
=lim(x→0)sinx(e^x-1)/(1-cosx)+lim(x→0)ln(1+x)/tanx
=lim(x→0)x^2/(1/2x^2)+lim(x→0)x/x
=2+1
=3