Question

Verify the identity

Answer 1

Given:

Given that we need to prove the identity $\sin x+\sin x \tan ^{2} x=\tan x \sec x$

Proof:

Step 1: Factor out the common term sin x, we get;

$\sin x\left(1+\tan ^{2} x\right)=tan \ x \ sec \ x$

Step 2: Using the identity $1+tan^2 x=sec^2x$

$\sin x \sec ^{2} x=tan \ x \ sec \ x$

Step 3: Reciprocating sec x, we get;

$\sin x \cdot \frac{1}{\cos ^{2} x}=tan \ x \ sec \ x$

Step 4: Splitting the denominator, we have;

$\frac{\sin x}{\cos x} \cdot \frac{1}{\cos x}=tan \ x \ sec \ x$

Simplifying, we get;

$\tan x \sec x=\tan x \sec x$

Thus, the identity is proved.