Trigonometric Identities, Sum and Difference, Half and Double

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

sin2u =

• (sinu)(cosu)
• 2(sinu)(cosu)
• (sinu)^2
• 2(sinu)^2

cos2u =

• 2(sinu)(cosu)
• (cosu)^2 - (sinu)^2
• 2(cosu)^2 - 2
• (sinu)^2 - (cosu)^2

Please choose the correct sum and difference formula:
sin (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

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

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
• D

Please find the sum or difference: sin(π/3)cos(π/6) + cos(π/3)sin(π/6)

• 0

• 1

• √3/4

• √3/2

Given sin α = -3/5, cos α = -4/5 and cos β = (2√5)/5, sin β = (-√5)/5

Find the difference:

sin (α-β)=

• 0

• (-10√5)/25

• (√2-√6)/4

• (√8)/4