Question

If $x\cos A=1$ and $y=\tan A,$ then $x^2-y^2$ is

• A. 0
• B. $\sqrt{2}$
• C. 2
• D. 1

Answer 1

The correct option is D 1

Given, $xcosA=1\Rightarrow x=\frac{1}{cosA}=secA$
$\therefore x^2-y^2=se{c}^{2}A-ta{n}^{2}A$
$\Rightarrow x^2-y^2=1$
Option D is correct.