Question

Find the value of $9se{c}^{2}a–9{\tan }^{2}a$

Answer 1

Compute the required value

Given expression is $9se{c}^{2}a–9{\tan }^{2}a$

Let $x=$$9se{c}^{2}a–9{\tan }^{2}a$

$\Rightarrow x=9(se{c}^{2}a–{\tan }^{2}a)$ { $\because se{c}^{2}a-{\tan }^{2}a=1$}

$\Rightarrow x=9\left(1\right)=9$

Hence the required value is $9$