lim (x → 0) (cos x) LOVE (1 / sin 2x) =?

lim (x → 0) (cos x) LOVE (1 / sin 2x) =?

f (x) = (cos x) ^ (1 / sin 2x), lnf (x) = 1 / (sin2x) ln cos x = ln (cosx) / sin2x
lim (x - > 0) lnf (x)
= lim (x - > 0) ln (cosx) / sin2x ln (1 + cosx - 1) cosx - 1
= lim (x - > 0) (cosx - 1) / (2x) cosx - 1 - x & # 178; / 2
= lim (x - > 0) (- x & # 178; / 2) / (2x)
= 0
오리지널