Question

sina ½ sin ( a + b) + sin(a = b)] OA. cos a OB.. sina OC. sinb D. cos b

Answer 1

Answer:

A. cos a

Explanation:

The relevant trigonometric formula we have is

$\sin a\cos a=\frac{1}{2}[\sin(a+b)+\sin(a-b)]$

Now comparing the above formula with the one given in the question tells us that the missing term in the equation is cos a.

Therefore, choice A is the right answer!