Question

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

Answer 1

A. cos a

Step-by-step explanation:

The relevant trigonometric formula we have is

`\sin a\cos a=(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!