Double Angle Formulas

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 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

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 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 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

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

• 24/7
• 7/25
• 24/25
• 1/2

Find what formula makes this true sin2u =

• (sinu)(cosu)

• 2(sinu)(cosu)

• (sinu)^2

• 2(sinu)^2

Find what formula makes this true cos2u =

• 2(sinu)(cosu)

• (cosu)^2 - (sinu)^2

• 2(cosu)^2 - 2

• (sinu)^2 - (cosu)^2

If cosx = - 4/5, find secx. (old trig problem)

• -5/4

• -3/5

• 5/3

• √3/2

Using the second identity, find Cos(50) (50 is the whole thing, take half and find the formula)

• sin²(25) - cos²(25)

• cos²(50) - sin²(50)

• cos²(25) - sin²(25)

• sin²(50) - cos²(50)