SOLUTION: Simplify (not solve!): a. Sin8a + Sin9a + Sin10a + Sin11a + Sin12a Cos 8a + Cos9a + Cos10a + Cos11a + Cos12a b. Cos^2[ (3pi/8) + (a/4) ] - Cos^2 [ (11pi/8) + (a/4)

Algebra ->  Trigonometry-basics -> SOLUTION: Simplify (not solve!): a. Sin8a + Sin9a + Sin10a + Sin11a + Sin12a Cos 8a + Cos9a + Cos10a + Cos11a + Cos12a b. Cos^2[ (3pi/8) + (a/4) ] - Cos^2 [ (11pi/8) + (a/4)       Log On


   

Question 233975: Simplify (not solve!):
a.
Sin8a + Sin9a + Sin10a + Sin11a + Sin12a
Cos 8a + Cos9a + Cos10a + Cos11a + Cos12a
b.
Cos^2[ (3pi/8) + (a/4) ] - Cos^2 [ (11pi/8) + (a/4) ]

Answer by nyc_function(2741) About Me  (Show Source):
You can put this solution on YOUR website!
All you have to do is combine like terms.
I will do (a) and you can do (b).
Sin8a + Sin9a + Sin10a + Sin11a + Sin12a
Cos 8a + Cos9a + Cos10a + Cos11a + Cos12a = sin50a + cos50a