Precalculus Trig Identities Sum and Difference

• A
• B
• C
• D

• A
• B
• C
• D

Use Sum or Difference Identities to find the exact value of each expression.
cos(75°)

• 1/4

• √6/4 - √2 / 4

• √6 + √2 / 4

• -√6/4 - √2 / 4

Find the exact value of the expression.
sin(5π/12)cos(π/4) - cos(5π/12)sin(π/4)

• 1/2

• -1/2

• -√(2)/2

• √(3)/2

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 expression as the sine or cosine of a single angle: \cos94\degree\cos18\degree+\sin94\degree\sin18\degree