WorksheetsTrig Identities
Total questions: 11
Worksheet time: 3hrs 45mins
Name
Class
Date
1.
Use sum or difference angles identity to find the exact value for sin (−15o)
a)
46+2
b)
46−2
c)
42−6
d)
−23
2.
Use sum or difference angles identity to find the exact value for cos105o
a)
46+2
b)
46−2
c)
4−6−2
d)
42−6
3.
Find the exact value of sin 2x if sin x = 12/13 and x is in the first quadrant.
a)
120/169
b)
25/169
c)
60/169
d)
5/13
4.
Use a double-angle identity to find the exact value of each expression
cos θ = 4/5 and 270° < θ < 360°
Find sin 2θ
cos θ = 4/5 and 270° < θ < 360°
Find sin 2θ
a)
-1/5
b)
24/25
c)
-24/25
d)
-25/24
5.
cos(2x) is NOT equal to which of the following?
a)
1 - sin2x
b)
2cos2x - 1
c)
1 - 2sin2x
d)
cos2x - sin2x
6.
Find the exact value of each expression
sin θ = −3/5 and 3π/2 < θ < 2π Find tan θ/2
a)
-1/3
b)
-√3
c)
√3/3
d)
-1
7.
Use the Half-angle formulas to find the exact value of each expression
cos 165º
cos 165º
a)
-√(2+√3)/2
b)
-√(2-√3)/2
c)
√(2+√3)/2
d)
√(2-√3)/2
8.
Use the Half-angle formulas to find the exact value of each expression
sin 22.5º
sin 22.5º
a)
√(2 + √3)/2
b)
√(2 - √2)/2
c)
√(2 + √2)/2
d)
√(2 - √3)/2
9.
Assume A and B are positive acute angles. If sinA=15/17 and cosB=4/5, find the cos(A - B).
a)
3/8
b)
8/17
c)
-13/85
d)
77/85
10.
If X is in Quadrant IV and tanX = 28/45, find the cos2X.
a)
2809/2520
b)
2520/2809
c)
1241/2809
d)
2809/1241
11.
Solve cos2x+sin2x=0 if the domain is [0, 360]
a)
{90, 270}
b)
{0 180}
c)
{30, 150}
d)
no solution
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