Question

Simplify :
4(1 – $si{n}^2\theta$) (1 + $ta{n}^2\theta$)

Answer 1

Using the identity,
1 - $si{n}^2\theta$ = $co{s}^2\theta$ and
1 + $ta{n}^2\theta$ = $se{c}^2\theta$

We have, 4(1 – $si{n}^2\theta$) (1 + $ta{n}^2\theta$)
$=4co{s}^2\theta \times se{c}^2\theta =4(\because sec\theta =\frac{1}{cos\theta })$