Question

(tan^2 20 - sin^2 20 ) / (tan^2 20 . sin^2 20)

Answer 1

see this can be done by splitting the numerator that is
(tan^2 20 / tan^2 20×sin^2 20) - (sin^2 20/tan^2 20×sin^2 20)
after this you will get
(1/sin^2 20) - (1/tan^2 20)
which will be equal to
cosec^2 20 - cot^2 20
using formula (cosec^2x - cot ^2 x = 1)
therefore it will be equal to 1