We have,
Differentiate the following functions with respect to x:
ddx{(1−2 tan x)(5+4 sin x)}
=(5+4 sin x)ddx(1−2 tan x)+(1−2 tan x)ddx(5+4 sin x) [Using product rule]
=(5+4 sin x)(0−2 sec2x)+(1−2 tan x)(0+4 cos x)
=−10sec2x−8 sinx×sec2x+4cosx−8 cosx×tan x
=4(−52sec2x−2 sin x×1cos2x+cos x−2 cos x×sin xcos x)
=4(−52sec2x−2 tanx sec x+cos x−2 sin x)
=4(cos x−2 sin x−2 tanx secx−52sec2x)