Question

The value of $\left[\right(secA+tanA\left)\right(1-sinA\left)\right]$ is equal to

• A. $ta{n}^{2}A$
• B. $si{n}^{2}A$
• C. cos A
• D. sin A

Answer 1

The correct option is C cos A

$\left[(\sec A+\tan A)(1-\sin A)\right]$

$\Rightarrow \left[\left(\frac{1+\sin A}{\cos A}\right)(1-\sin A)\right]$

$\Rightarrow \frac{1-{\sin }^{2}A}{\cos A}=\frac{{\cos }^{2}A}{\cos A}$

$\Rightarrow \cos A$

Hence, the answer is $\cos A.$