WorksheetsUnit 9 simplifying trig identities
Total questions: 239
Worksheet time: 10hrs 11mins
What is csc(x) equivalent to?
sinx1
tanx1
sin(x)
cosx1
cos 2 x + sin 2 x=
Simplify
secθ
cos²θ
sin²θ
cos2xsin2x
Simplify: (secx-1)(secx+1)
Hint: you will need to FOIL first
tan2x
sinx
cot2x
cosx
tan2x + 1 = secx
tan(x)csc(x)
cos x1
1
cot x
-1
Verify the following:
cos²x
sin²x
cot²x
tan²x
Which of the following is not a pythagorean identity?
cot2x + 1 = csc2x
csc2x + 1 = cot2x
cot2x - csc2x = -1
csc2x - cot2x = 1
sin x =
cos x
1/cosx
1/secx
1/cscx
cos x =
sin x
sin2x-1
1/sec x
1/csc x
tan x =
sinx/cos x
cosx/sinx
1/cotx
sec2x
sec x =
1/cosx
1/sinx
1/cscx
1/tanx
csc x =
1/cosx
1/sinx
cot2x-1
1/secx
cotx =
sinx/cosx
cosx/sinx
1/tanx
1/cotx
sin2x + cos2x =
1
1/sinx
sec2x
csc2x
1 - sin2x =
cos2x
cos2x+1
csc2x
tan2x
tan2x + 1 =
csc2x
sec2x
sec2x - 1
cscx
1 + cot2x =
sec2x
sec2x - 1
tan2x
csc2x
1 - cos2x =
sec2x
csc2x
sin2x
sec2x - 1
sec2x =
sinx + cosx
1 + csc2x
1 + tan2x
1 - sin2x
csc2x - 1 =
cot2x
tan2x
cot2x + 1
sin2x + cos2x
sec2x - 1 =
cot2x
csc2x
1 + tan2x
tan2x
1/cosx =
secx
cscx
tanx
sinx
1/tanx =
tanx
sinx/cosx
cotx
sin2x
cos2x =
1 - sec2x
1 - sin2x
sin2x
1
1/sinx
tanx
secx
cscx
cosx
1 + tan2θ = sec2θ
sin2θ + cos2θ = 1
Simplify
tanxcscxcosx
1/cos x
1
cot x
-1
Simplify
sinθ(cscθ−sinθ)
secθ
cos²θ
sin²θ
sin²θ/cos²θ
Simplify tanx(cotx + cscx)
1 + sec x
1 + csc x
sec x - 1
tan² x
What happens when you multiply two reciprocal functions?
You get a pythagorean identity
It equals 1
You get a quotient identity
It equals 0
Simplify (cscx+1)(cscx−1)
csc2x+1
tan2x
cot2x
2cscx
1−sin2x =
sin2x
cos2x
sec2x
csc2x
sec(u)
cos(u)
csc(u)
sin(u)
cot(u)
csc(u)
cos(u)
tan(u)
sin(u)
cot(u)
cos(90 - u)
sec(u)
csc(u)
tan(u)
sin(u)
cot(u)
sin(90 - u)
sec(u)
cos(u)
tan(u)
csc(u)
cot(u)
sec(u)
cos(u)
tan(u)
sin(u)
cot(u)
sec(u)
cos(u)
tan(u)
sin(u)
csc(u)
cos(-u)
cos(u)
-cos(u)
sin(u)
-sec(u)
sec(u)
sec(-u)
cos(u)
-cos(u)
sin(u)
-sec(u)
sec(u)
sin(-u)
cos(u)
-sin(u)
sin(u)
-csc(u)
csc(u)
csc(-u)
cos(u)
-sin(u)
sin(u)
-csc(u)
csc(u)
tan(-u)
tan(u)
-cot(u)
sin(u)
-tan(u)
cot(u)
cot(-u)
tan(u)
-cot(u)
sin(u)
-tan(u)
cot(u)
Select all that are Pythagorean Identities.
sin2(u) + cos2(u) = 1
sin2(u) - cos2(u) = 1
tan2(u) + 1 = sec2(u)
cot2(u) + csc2(u) = 1
cot2(u) + 1 = csc2(u)
Simplify: secθsinθ
cos θ
csc θ
tan θ
cot θ
Simplify: cosθtanθ
sin θ
cos θ
tan θ
csc θ
Simplify: (secθ−1)(secθ+1)
sin 2 θ
cos 2 θ
tan 2 θ
sec 2 θ
Simplify: (cos θ)(sec θ−cosθ)
sin2θ
cos2θ
csc2θ
sec2θ
Simplify: tanx cotx
sin x
cos x
−1
1
Simplify: sec2x−1sec2x
sin2x
csc2x
cos2x
sec2x
Simplify: secx−tanxsinx
sinx
cosx
cscx
secx
Simplify: secx1−sin2x
sin2x
cos2x
sin3x
cos3x
Simplify: cotxcos2(−x)cscx
−sinx
−cosx
sinx
cosx
Simplify: 1+tan2xsin2x+cos2x+cot2x
cot2x
tan2x
csc2x
sec2x
Which of the following is NOT a pythagorean identity?
sin2x + cos2x = 1
1 - cos2x = sin2x
1 - sin2x = cos2 x
sin2x - cos2x = -1
Which of the following is NOT a pythagorean identity?
1 + tan2x = sec2x
sec2x - 1= tan2x
tan2x - sec2x = -1
tan2x - 1 = -sec2x
tan(x)csc(x)
Simplify (Hint: you will need to FOIL first)
sinθ
cot²θ
tan²θ
cos²θ
Given tanx=129 and the angle is in quadrant I. What is the value of secx?
secx=35
secx=54
secx=45
sec=34
Simplify the expression cotxsin2xcscx
sinx
cosx
tanx
cscx
Simplify the expression csc2x(1−sec2x)
−csc2x
cosx
−sec2x
tanx
cos(θ)=
−cos(θ)
cos(−θ)
−cos(−θ)
sin(θ)=
−sin(θ)
sin(−θ)
−sin(−θ)
tan(θ)=
−tan(θ)
tan(−θ)
−tan(−θ)
cos(−θ)=
−cos(θ)
cos(θ)
−cos(−θ)
sin(−θ)=
−sin(θ)
sin(θ)
−sin(−θ)
tan(−θ)=
−tan(θ)
tan(θ)
−tan(−θ)
cos(2π+θ)=
sin(θ)
−sin(θ)
sin(2π+θ)=
cos(θ)
−cos(θ)
cos(π+θ)=
cos(θ)
−cos(θ)
cos(π−θ)=
cos(θ)
−cos(θ)
sin(π−θ)=
sin(θ)
−sin(θ)
sin(π+θ)=
sin(θ)
−sin(θ)
tan(π+θ)=
tan(θ)
−tan(θ)
tan(π−θ)=
tan(θ)
−tan(θ)
tanB (cotB + tanB) = sec2B
(secx-1)(secx+1).
Hint: you will need to FOIL first
Sin means
opposite / hypotenuse
adjacent / hypotenuse
opposite / adjacent
adjacent / opposite
True or False, cos(x)/tan(x) = cot(x)cos(x)
True
False
True or False, tan(x)cot(x) = 1?
True
False
True or False, (cot(x)) / (sec(x)) = sin(x)?
True
False
True or False, cos(x)/cot(x) = sin(x)?
True
False
cos 2 x + sin 2 x=
tan2x + 1 = secx
From the given list, select all equivalent forms of the Pythagorean Identity
cos2θ+sin2θ=11+tan2θ=sec2θ
1+cot2θ=sec2θ
1+tan2θ=csc2θ
1+cot2θ=csc2θ
Select all correct even/odd identities from the given list.
sin(−x)=sin(x)
cos(−x)=cos(x)
tan(−x)=−tan(x)
sin(−x)=−sin(x)
cos(−x)=−cos(x)
From the given list, select all equivalent forms of the Pythagorean Identity
cos2θ+sin2θ=1sin2θ=cos2θ−1
cos2θ=1−sin2θ
cos2θ=1+sin2θ
sin2θ=1−cos2θ
What is the best first step for proving 1+cosx1=sin2x1−cosx ?
Multiply the numerator and denominator by the conjugate (1−cosx)
Square the numerator and denominator
Use a Pythagorean Identity for the denominator to change the (1+cosx) to (sin2x +cos2x+cosx)
Split up the denominator
Which of the following is the best first step to verify the identity
cos4x−sin4x=2cos2x−1Split up the (sin4x) as (sin2x)(sin2x) to set up a Pythagorean Identity substitution
Split up the (cos4x) as (cos2x)(cos2x) to set up a Pythagorean Identity substitution
Factor the left side using the difference of squares
Use a Pythagorean Identity on the right side to change (2cos2x−1) to (2(1−sin2x)−1)
Find the exact value of
cos105°42+6
22−3
46−2
42−6
If cosA=53 where 0°≤A≤90° and sinB=135 where 90°≤B≤180° find cos(A+B) .
(a)
Write the following as a single trigonometric expression, then evaluate the expression.
sin150°=23
sin150°=21
sin(−76°)≈−0.9703
sin(−76°)≈0.2419
cos(75°)
cos(175)cos(55)+sin(175)sin(55)
a solution to
sin θ = √(3) / 2 ?
cos (α-β) =
cos(20)cos(40) - sin(20)sin(40)
If sinA=54,tanB=125, and A and B are first quadrant angles, what is the value of sin(A+B) ?
6563
−6533
6533
−6563
Find the exact value of the expression.
sin(125π)cos(4π)−cos(125π)sin(4π)
21
−21
−22
−23
Find the exact value of sin2x if sinx=1312 and x is in the first quadrant.
169120
16925
16960
135
Use a sum or difference formula to find an exact value of sin(127π)
23
4−2−6
42+6
2−3
If cos θ = 4/5 and 23π<θ<2π
Find sin 2θ
−51
2524
−2524
−2425
If sinA=53,sinB=32, and ∠A and ∠B are in the first quadrant, what is the value of cos(A−B)?
−32
1545−6
545+2
1545+6
If sinθ=35 and 2π<θ<π , then cos2θ equals
31
−31
91
−91
Use sum or difference angles identity to find the exact value for sin (12−π)
46+2
46−2
42−6
−23
Find the exact value of sin2θ if sinθ=1312 and θ is in the first quadrant.
120/169
25/169
60/169
5/13
If cos θ = 4/5 and 23π<θ<2π , find sin 2θ
-1/5
24/25
-24/25
-25/24
If A and B are first quadrant angles with sinA=15/17 and cosB=4/5, find cos(A - B).
3/8
8/17
-13/85
77/85
cos(20)cos(40) - sin(20)sin(40)
sin(5π/12)cos(π/4) - cos(5π/12)sin(π/4)
cos (265 - 25) =
cos (5π/18 - π/9)
cos(175)cos(55)+sin(175)sin(55)
cos(20)cos(40) - sin(20)sin(40)
cos (265 - 25) =
Please find the sum or difference:
cos (α+β)=
Please find the sum or difference:
sin (α-β)=
sin(x+π)
sin(π/12)
cos(75°)
cos(π/3)cos(2π/3)-sin(π/3)cos(2π/3)
cos (5π/18 - π/9)
cos(175)cos(55)+sin(175)sin(55)
sin(5π/12)cos(π/4) - cos(5π/12)sin(π/4)
cos(175)cos(55)+sin(175)sin(55)
a solution to
sin θ = √(3) / 2 ?
cos (α-β) =
cos(20)cos(40) - sin(20)sin(40)
Which of the following is the same as cos (A+B)
sinAcos B + cos A sin B
sin A cos B − cos A sin B
cos A cos B + sin A sin B
cos A cos B − sin A sin B
Which of the following is equivalent to tan (A−B)
tan A − tan B
1+ tanAtanBtan A −tan B
1− tanAtanBtan A +tan B
cos Bsin A
Expand sin (33o +42o)
sin 75o
sin 33ocos42o+cos33osin42o
sin 33ocos42o−cos33osin42o
cos33ocos42o+sin33osin42o
Expand cos (5π+6π)
cos5πcos6π−sin5πsin6π
cos5πcos6π+sin5πsin6π
cos 112π
cos5πsin6π−cos5πsin6π
cos75ocos15o−sin75o sin15o is equivalent to
sin 90o
sin 60o
cos 90o
cos 60o
1−tan45otan30otan45o+tan30o is equivalent to
tan75o
tan 15o
cos30osin45o
tan90o
Use sum or difference angles identity to find the exact value for cos105o
46+2
46−2
4−6−2
42−6
Use sum or difference angles identity to find the exact value for sin (−15o)
46+2
46−2
42−6
−23
Given sinx=53and siny=32, where x and y are both in first quadrant. Evaluate sin(x+y)
1535+8
1545+6
1525+12
545+2
If sinA=53,sinB=32, and ∠A and ∠B are acute angles, what is the value of cos(A−B)?
−32
1545−6
545+2
1545+6
If cosA=31 , then the positive value of tan 2A ?
2
3
33
22
Factor: sec2x − secx − 2
(sec x)(secx − 2)
(secx − 2)(secx − 1)
(secx − 2)(secx + 1)
(secx + 2)(secx − 1)
csc2x = 2 is equivalent to sin2x = ½
True
False
On the domain [0, 2π), solve this equation 0 = sinx(sinx − 1)
0, π
0, π, ½π
½π
0, 90, 270
Factor 0 = sin2x − sinx
0 = sinx(sinx)
0 = sinx(1 − sinx)
0 = cosx(sinx − 1)
0 = sinx(sinx − 1)
Choose a good way to start solving this equation
tanx sin2x = 2 tanx
divide tanx from both sides
factor out tanx
subtract 2 tanx from the left and then factor tanx out
cancel sin2x out
Why doesn't 2cosx − 3 = 0 have solutions?
cosx is never bigger than one
cosx is never equal to a fraction
Actually, this equation does have a solution, x = π
This equation will have a solution tomorrow.
Find an expression equivalent to the following:
sinθsecθtanθ
sec2θ
cotθ
tan2θ
cos2θ
If secθ=−45 and 180o<θ<270o , find tanθ .
−53
−54
43
53
Simplify the following:
tan2θtan2θ+1
csc2θ
-1
tan2θ
1
Simplify the following:
sinxtanx+cosx1
2 tan2x
2 cosx
2cosx−1
2 secx
Use a sum or difference identity to find the exact value of sin105o .
4−2−6
46−2
46+2
42−6
Find the value of tan(α−β) if cosa=54 , sinβ=−135 , 270o<α<360o , and 270o<β<360o .
6316
−6316
−3356
3356
Which expression is equivalent to the following:
cos(π+θ)
−cosθ
cosθ
−sinθ
sinθ
Which expression is NOT equivalent to the following:
cos2θ
2cos2θ−1
1−2sin2θ
cos2θ+sin2θ
cos2θ−sin2θ
If sinθ=0.6 and 90o<θ<180o , find the exact value of sin2θ .
-0.6
-0.96
0.96
0.28
If cosθ=−53 and θ has its terminal side in Quadrant II, find the exact value of tan2θ .
2524
257
724
−257
Use a half-angle identity to find the exact value of cos75o .
212+3
212−3
212+2
−211+3
Solve 2cosx−1=0 for 0≤x<2π .
6π;65π
3π; 35π
3π; 32π
67π; 611π
Solve 2sin2x−sinx=0 for principal values of x.
60o; 120o
0o; 150o
0o; 30o
60o
Solve 2sinx+3=0 for 0≤x<2π .
34π;35π
32π;34π
67π;611π
65π;67π
Find a numerical value of one trigonometric function of x if the following is true:
secxcotx=4
cscx=41
secx=41
secx=4
cscx=4
Given sin⊖ = 3−1 and cos⊖ = 322 , find the exact value for tan⊖.
−22
42
−3
4−2
Given cos ⊖ = 53 and tan⊖ < 0 , find the exact value for sin⊖ using pythagorean identities.
353
522
2522
5−22
The expression sin2x+cos2x−b2 is equal to
1
b2
(1+b)(1−b)
sinxcosx−b
Pythagorean: sin2x−1=?
−cos2x
cos2x
cos2x−1
1−cos2x
csc(x)sin(x) + cot2(x)
A. tan2(x)
B. sec2(x)
C. csc2(x)
D. -csc2(x)
Select the MOST SIMPLIFIED answer for the problem:
sin2x1−cos2x
sin2x
cos2x
1
sin2xsin2x
Select the MOST SIMPLIFIED answer for the problem:
1−sin2xcot2x
1
cos2xcot2x
sin2x1
csc2x
3(csc2x−cot2x)
0
1
2
3
Select the MOST SIMPLIFIED answer for the problem:
sin2xsec2x−1
cos2x1
secx
sec2x
cosx1
Select the MOST SIMPLIFIED answer for the problem:
1+cot2θcot2θ
cosθ
cos2θ
1
(sin2θcos2θ)(1sin2θ)
Select the MOST SIMPLIFIED answer for the problem:
1−cos2x1−sin2x
sinxcosx
sin2xcos2x
tan2x
cot2x
secxcos2x+sin2x
secx1
sinx
cosx
Select the MOST SIMPLIFIED answer for the problem:
sin2x+sinx+cos2x−1
sinx
2
0
Solve on the Interval [0,2π)
tan(x)+1=2
0 and π
3π/4 and 7π/4
π/4 and 5π/4
3π/4 and 5π/4
Solve
cos2θ = ½
on θ∈[0, 2π)
θ = π /4, 7π /4
θ = π /4, 3π /4
θ = 3π /4, 5π /4
θ = π/4, 3π/4, 5π/4, 7π/4
Which of these is equivalent to 2cos2x − 3cosx = 0 ?
-cos2x = 0
cosx(2cosx + 3) = 0
cosx(2cosx − 3) = 0
cos x = ⅔
Choose a good way to start solving this equation
tanx sin2x = 2 tanx
divide tanx from both sides
factor out tanx
subtract 2 tanx from the left and then factor tanx out
cancel sin2x out
Simplify: cotxcos2(−x)cscx
−sinx
−cosx
sinx
cosx
