Question

Tentukan lim tan x-1/cos2x
x→π/4

Answer 1

Lim x-> π/4  (tan x - 1) / cos 2x .... gunakan turunan
= sec² x / - 2 sin 2x
= 1/ - 2 cos² x sin 2x
= 1/  -2(cos π/4) . sin 2(π/4)
= 1 / -2( 1/2 √2)² . (1)
= 1/ -2(1/2)(1)
= 1/-1
= -1