Sum Difference Identities

• 0.2588

• 0.6503
  

• 0.2588

• 0.9218

Write the expression as the sine or cosine of a single angle:

$\cos\left(7y\right)\cos\left(3y\right)-\sin\left(7y\right)\sin\left(3y\right)$

Write the following expression as the sine, cosine, or tangent of an angle.
cos(175)cos(55)+sin(175)sin(55)

• sin(120)

• cos(120)

• cos(230)

• sin(230)

Find the exact value.

• A

• B

• C

• D

Please choose the correct sum and difference formula:
cos (α-β) =

• sin α cos β + cos α sin β

• sin α cos β - cos α sin β

• cos α cos β - sin α sin β

• cos α cos β + sin α sin β

• A
• B
• C