Question

If $A$ and $B$ are acute angle such that $\sin A=\cos B$, then $(A+B)=.....$

• A. ${45}^{\circ }$
• B. ${60}^{\circ }$
• C. ${90}^{\circ }$
• D. ${180}^{\circ }$

Answer 1

The correct option is C ${90}^{\circ }$

$\sin A=\cos B$

$\Rightarrow \sin A=\sin ({90}^o-B)$
$\Rightarrow A={90}^o-B$
$\Rightarrow A+B={90}^o$

Therefore, Answer is ${90}^o$