Sum and Difference formulas and double angle Trig HW

Find the exact value of the expression.
cos(20)cos(40) - sin(20)sin(40)

• 1/4
• 1/2
• √(3)/2
• √(3)

Tags

CCSS.HSF.TF.C.9

Find the exact value. 
cos (265 - 25) = 

• 53/12
• -√(3)/2
• -1/2
• √(3)/2

Tags

CCSS.HSF.TF.C.9

Find the exact value.
cos (5π/18 - π/9)

• √(3)/2
• 1/4
• 1/2
• 1

Tags

CCSS.HSF.TF.C.9

Given sin α = -3/5, cos α = -4/5 and cos β = (2√5)/5, sin β = (-√5)/5
Please find the sum or difference:
cos (α+β)=

• (-11√5)/25
• (-2√5)/25
• (√2-√6)/4
• 2

Tags

CCSS.HSF.TF.C.9

Simplify
sin(x+π)

• -1
• csc(x)
• sin(x)
• -sin(x)

Tags

CCSS.HSF.TF.C.9

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

• 1/4
• ( √(6) - √(2) ) / 4
• (√(6) + √(2)) / 4
• (-√(6) - √(2)) / 4

Tags

CCSS.HSF.TF.C.9

Find the exact value

• 2 - √3

• 2 + √3

• -2 - √3

• -2 + √3

Tags

CCSS.HSF.TF.C.9

sin 105º

• √3/2
• -1/4(√2 + √6)
• 1/4 (√2 + √6)
• 2-√3

Tags

CCSS.HSF.TF.C.9

sin2u =

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

Tags

CCSS.HSF.TF.C.9

cos2u =

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

Tags

CCSS.HSF.TF.C.9