L.H.S

`(tan^2(theta))/sec(theta) = tan^2(theta)*cos(theta) = tan(theta)*cos(theta)*{tan(theta)} =`

`tan(theta)*cos(theta)*{sin(theta)/cos(theta)} = tan(theta)*sin(theta) = ` R.H.S

L.H.S

`(tan^2(theta))/sec(theta) = tan^2(theta)*cos(theta) = tan(theta)*cos(theta)*{tan(theta)} =`

`tan(theta)*cos(theta)*{sin(theta)/cos(theta)} = tan(theta)*sin(theta) = ` R.H.S