Question

If $x+y=\frac{\pi }{2}$, then prove that $\cos (x+y)=0$

Answer 1

$as\theta \to \left(\frac{\pi }{2}\right),b\to 0\therefore cos(x+y)=cos\left(\frac{\pi }{2}\right)=\left(\frac{0}{h}\right)=0$