Sum and Difference Angles Trig Identities

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

• 1/2
• -1/2
• -√(2)/2
• √(3)/2

• A
• B
• C
• D

• 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