Question

If θ < 90°, find the value of: `tan^2θ - (1)/cos^2θ`

Answer 1

Since θ <90°,
Consider θ = 45°

∴ `tan^2 θ - (1)/cos^2θ`

= `tan^2 45° - (1)/(cos^2 45°)`

= `(1)^2 - (1)/(1/sqrt(2))^2`

= `1 - (1)/(1/2)`

= 1 - 2
= -1.