SOLUTION: Prove the identity: {{{sin(a + B) sin (a-B) = (sin(a))^2-(sin(B))^2}}} (x is theta)

Algebra ->  Trigonometry-basics -> SOLUTION: Prove the identity: {{{sin(a + B) sin (a-B) = (sin(a))^2-(sin(B))^2}}} (x is theta)      Log On


   

Question 138819: Prove the identity: sin%28a+%2B+B%29+sin+%28a-B%29+=+%28sin%28a%29%29%5E2-%28sin%28B%29%29%5E2 (x is theta)
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
Note: I'm only manipulating the left side. I'm not touching the right side. I'm only showing it for comparison.



Start with the given equation


Expand by using the Sum-Difference Formulas


Foil


Combine like terms


Replace with . Replace with




Distribute


Combine like terms




So we've just proven that



is an identity.