Question

If $x=\sqrt{a}sin\alpha$ and $y=\sqrt{a}cos\alpha$. Find the value of $y^2$ + $x^2$.

• A. $\alpha$
• B. $\alpha$ + a
• C. a
• D. $a^2$

Answer 1

The correct option is C a

x = $\sqrt{a}sin\alpha$ and y = $\sqrt{a}cos\alpha$

$x^2$ = $\sqrt{a}si{n}^2\alpha$ and $y^2$ = $\sqrt{a}co{s}^2\alpha$
$\Rightarrow$ $y^2$ + $x^2$ = $a(co{s}^2\alpha +si{n}^2\alpha )=a$