Sum and Difference Identities

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

Tags

CCSS.HSF.TF.C.9

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)

Tags

CCSS.HSF.TF.C.9

• A
• B
• C
• D

Tags

CCSS.HSF.TF.C.9

Given sin α = -3/5 and is in Quadrant 3 and cos β = (2√5)/5

and is in Quadrant 4. Please find the sum:

sin (α+β)=

• 0

• (-2√5)/25

• (√2-√6)/4

• (√8)/4