Double Angle and Half Angle Identities

Use a double-angle or half-angle identity to find the exact value of each expression cos θ = 4/5 and 270° < θ < 360°Find sin 2θ

• -1/5

• 24/25

• -24/25

• -25/24

Use a double-angle identity to find the exact value of each expression
cos θ = 4/5 and 270° < θ < 360°
Find sin 2θ

• -1/5

• 24/25

• -24/25

• -25/24

Use a double-angle or half-angle identity to find the exact value of each expression
cos θ = 4/5 and 270° < θ < 360°Find sin 2θ

• -1/5

• 24/25

• -24/25

• -25/24

Use a double-angle or half-angle identity to find the exact value of each expression
sin θ = −3/5 and 3π/2 < θ < 2π Find tan θ/2

• -1/3

• -√3

• √3/3

• -1

Find the exact value of sin 2x if sin x = 12/13 and x is in the first quadrant. 

• 120/169

• 25/169

• 60/169

• 5/13

Use the information about the angle θ, 0≤θ<2π to find the exact value of
sin (2θ)
sin θ= 3/5 , 0<θ<π/2

• 24/7

• 7/25

• 24/25

• 1/2

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

Using the second identity, find Cos(50)

• sin²(25) - cos²(25) 

• cos²(50) - sin²(50)

• cos²(25) - sin²(25)

• sin²(50) - cos²(50) 

Using the fourth identity, find Cos(120)

• 2sin²(120)

• 1+2sin²(120)

• 1+2sin²(60)

• 1-2sin²(60)