How to complete the identity of sin(a +B) +sin(a -B)?

Question

How to complete the identity of sin(a +B) +sin(a -B)?

Answer 1

sin(a+B)+sin(a-B)=

2sin[(1/2)(a+B+a-B)]*

cos[(1/2)(a+B-(a-B))]=

2sinacosB

Answer 2

Get a good math book or just go to goggle and type in Sin(a+b)

then type in Sin(a-b) you will be amazed at what turns up.  Just like ole Bilbo said, you put one foot in front of the other and you never know where you might end up.

Answer 3

sin(a+B)=sin(a)cos(B)+cos(a)sin(B)

sin(a-B)=sin(a)cos(B)-cos(a)sin(B)

add:

sin(a +B) +sin(a -B)= 2 sin(a) cos(B)