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1
Algebra 3 Assignment Sheet
WELCOME TO TRIGONOMETRY, ENJOY YOUR STAY
(1) Assignment # 1 − Complete the circle diagram
(2) Assignment # 2 − Sine & Cosine functions chart
I Definition of radian: Radians are an angular measurement. One radian is the measure of a central angle of a circle that is subtended by an arc whose length is equal to the radius of the circle.
Therefore: arc length = angle in radians x radius
The radius wraps itself around the circle 2π times. Approx. 6.28 times. Therefore 360� = 2π R
Dividing you get 2
1360
Rπ=�
�
………..1180
Rπ=�
�
Conversely ………………………...180
1RRπ
=�
Ex. Change 60� to radians.
Change 4
Rπto degrees.
Convert the following from degrees to radians or vice versa:
1. 36� 2. 320� 3. 195 0
4. 15
π 5.
17
20
π 6.
5
3
π
0 ,R
2π
2
π
π
3
2
π
1 R
5
5
2 R
5
10
1
2
3
6
4
5
3
II UNIT CIRCLE:
The unit circle is the circle with radius = 1, center is located at the origin. What is the equation of this circle? Important Terms: A. Initial side: B. Terminal side: C. Coterminal angles: D. Reference angles: The initial and terminal sides form an angle at the center if the terminal side rotates CCW, the angle is positive if the terminal side rotates CW, the angle is negative unit circle positive negative coterminal
Coterminal angles have the same terminal side…. -45˚ and 315˚ or 3
π and
7
3
π
The reference angle is the acute angle made between the Terminal Side and the x-axis
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III GEOMETRY REVIEW 30 – 60 – 90° RIGHT TRIANGLES 45 – 45 - 90°
Therefore, for the Unit Circle, hypotenuse is always 1.
60 °
30 °
a 2a
3a
60 °
30 °
1/2 1
3 / 2
45 °
45 °
a
a
a 2
45 °
45 °
2 / 2
2 / 2
1
5
Algebra 3 Assignment # 1
6
Trigonometric Functions Let θ “theta” represent the measure of the reference angle. Three basic functions are sine, cosine and tangent. They are written as sin θ, cos θ, and tan θ
Right triangle trigonometry - SOHCAHTOA
sinopp
hypθ =
cosadj
hypθ =
tanopp
adjθ =
A. Find cos θ B. Find sin θ C. Find tan θ D. Find sin θ
θ
hyp
adj
opp
12 θ
5
13
θ
5
5 2
5 3
θ
6 9
θ
7 25
7
Triangles in the Unit Circle On the Unit Circle: I Where functions are positive II Reference Triangles A. Drop ⊥ from point to x-axis.
1
O
P(x,y)
A (1,0)
B (0,1)
x
y
=
=
=
sinθ
cosθ
tanθ
O
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B. Examples
1. Find sin 3
4π
2. Find cos3
4π −
Same as cos
5
4
R
π
3. Find sin 420° =
4. Find cos 13
6π −
=
5. Find sin π = cos π =
coterminal angles
coterminal angles
coterminal angles
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III Quadrangle Angles Def: An angle that has its terminal side on one of the coordinate axes. To find these angles , use the chart Find the sine, cosine for all the quadrangles. 0 0 sin 0 cos 0
90 sin cos2
180 sin cos
3270 sin cos
2
360 2 sin cos
R
R
R
R
R
π
π
π
π
° = = =
° = = =
° = = =
° = = =
° = = =
A (1,0)
B (0,1)
C (-1,0)
D (0,-1)
1
1
sin
cos
y
x
= =
= =
= =
sinθ y
cosθ x
ytanθ
x
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Algebra 3 Assignment # 2 Complete each of the following tables please.
Radian
Measure
11
3
π
5
4
π
19
6
π 3π
Degree
Measure 330� 450� 45− �
210− �
Sin
Cos
Radian
Measure
3
2
π−
7
3
π−
4
π
11
4
π
Degree
Measure 180− �
150� 780� 90�
Sin
Cos
11
Answers
Radian
Measure
11
3
π
11
6
π
5
4
π
5
2
π
19
6
π
4
π− 3π
7
6
π−
Degree
Measure 660� 330� 225� 450� 570� 45− �
540� 210− �
Sin 3
2−
1
2−
2
2− 1
1
2−
2
2− 0
1
2
Cos 1
2
3
2
2
2− 0
3
2−
2
2 −1
3
2−
Radian
Measure
3
2
π− −π
7
3
π−
5
6
π
4
π
13
3
π
11
4
π
2
π
Degree
Measure 270− �
180− �
420− �
150� 45� 780� 495� 90�
Sin 1 0 3
2−
1
2
2
2
3
2
2
2 1
Cos 0 −1 1
2
3
2−
2
2
1
2
2
2− 0
12
Other Trigonometric Functions
Sinθ Cosecant:
Cosθ Secant:
Tanθ Cotangent: http://mathplotter.lawrenceville.org/mathplotter/mathPage/trig.htm Find the following values