Answer 1

L.H.S. = tan²θ − sin²θ

= `sin^2theta/cos^2theta - sin^2theta`

= `sin^2theta (1/cos^2theta - 1)`

= `(sin^2theta(1 - cos^2theta))/cos^2theta`

= (sin²θ) (sin²θ) sec²θ

= sin⁴θ sec²θ

= R.H.S.