Question

If a and b are acute angle such that sina + cosb prove that a+b =90°​

Answer 1

Answer:

Using identity sin theta.cos theta=1

If a=45 degeee and d=45 degree

Sin45 degree.cos45 degree =1

Hence a=45 b=45

a+b=45+45=90

Hence proved

Step-by-step explanation:

Answer 2

Given :

• sin A = cos B

To Prove :

• A + B = 90°

Solution :

We are given,

sin A = cos B

Now, we know that,

$\Large \underline{\boxed{\bf{ cos \theta = sin (90^{\circ} - \theta) }}}$

$\sf : \implies sin A = sin (90^{\circ} - B)$

$\sf : \implies A = 90^{\circ} - B$

$\sf : \implies A + B = 90^{\circ}$

$\Large \underline{\boxed{\bf{A + B = 90^{\circ}}}}$

Hence, Proved.