Question

Pls ans fast tommorow is my exam​

Answer 1

hey Mark it as brainliest

Answer 2

${\huge {\mathfrak {\orange {Answer :-}}}}$

We have,

A + B + C = 180°

So, C + B = 180° - A.

Or, B + C = 90° - A/2

And when angles are acute, we can write that,

cos (90° - X) = sin X

Now,

➡️ cos [(C + B)/2]

= cos [(180° - A)/2]

= cos [90° - A/2]

= sin A/2. ⬅️

$<b>$ That's it..