Trig Identities

Use sum or difference angles identity to find the exact value for       $\sin\ \left(-15^o\right)$  

•  $\frac{\sqrt{6}+\sqrt{2}}{4}$  

•  $\frac{\sqrt{6}-\sqrt{2}}{4}$  

•  $\frac{\sqrt{2}-\sqrt{6}}{4}$  

•  $-\frac{\sqrt{3}}{2}$  

Tags

CCSS.HSF.TF.C.9

Use sum or difference angles identity to find the exact value for  $\cos105^o$  

•  $\frac{\sqrt{6}+\sqrt{2}}{4}$  

•  $\frac{\sqrt{6}-\sqrt{2}}{4}$  

•  $\frac{-\sqrt{6}-\sqrt{2}}{4}$  

•  $\frac{\sqrt{2}-\sqrt{6}}{4}$  

Tags

CCSS.HSF.TF.C.9

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

Tags

CCSS.HSF.TF.C.9

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

Tags

CCSS.HSF.TF.C.9

cos(2x) is NOT equal to which of the following?

• 1 - sin²x

• 2cos²x - 1

• 1 - 2sin²x

• cos²x - sin²x

Tags

CCSS.HSF.TF.C.9

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

Tags

CCSS.HSF.TF.C.9

Use the Half-angle formulas to find the exact value of each expression
cos 165º

• -√(2+√3)/2
• -√(2-√3)/2
• √(2+√3)/2
• √(2-√3)/2

Tags

CCSS.HSF.TF.C.9

Use the Half-angle formulas to find the exact value of each expression
sin 22.5º

• √(2 + √3)/2
• √(2 - √2)/2
• √(2 + √2)/2
• √(2 - √3)/2

Tags

CCSS.HSF.TF.C.9

Assume A and B are positive acute angles. If sinA=15/17 and cosB=4/5, find the cos(A - B).

• 3/8

• 8/17

• -13/85

• 77/85

Tags

CCSS.HSF.TF.C.9

If X is in Quadrant IV and tanX = 28/45, find the cos2X.

• 2809/2520

• 2520/2809

• 1241/2809

• 2809/1241