Quick Review Solutions 1. Find the circum ference ofthe circle w ith a radiusof4.5 in. 2. Find the radiusofthe circle w ith a circum ference of14 cm . 3. Given . Find if 2.2 cm and 9 in 7/ cm 4 rad 8.8 ians. s r s r cm 95.3 feetpersecond 4. Convert65 m ilesperhourinto feetpersecond. 5. Convert9.8 feetpersecond to m ilesper 6.681 m iles hour. per hour
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Quick Review Solutions. Why 360 º ? Navigation In navigation, the course or bearing of an object is sometimes given as the angle of the line of travel.
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Quick Review Solutions
1. Find the circumference of the circle with a radius of 4.5 in.
2. Find the radius of the circle with a circumference of 14 cm.
3. Given . Find if 2.2 cm and
9 in
7 / cm
4 rad 8.8ians. s r s r
cm
95.3 feet per second4. Convert 65 miles per hour into feet per second.
5. Convert 9.8 feet per second to miles per 6.681 miles hour. per hour
Why 360º?
Navigation
In navigation, the course or bearing of an object is sometimes given as the angle of the line of travel measured clockwise from due north.
Radian
A central angle of a circle has measure 1 radian if it intercepts an arc with the same length as the radius.
Example Working with Radian Measure
How many radians are in 60 degrees?
Example Working with Radian Measure
How many radians are in 60 degrees?
Since radians and 180 both measure a straight angle, use the conversion
factor radians / 180 1 to convert radians to degrees.
radians 6060 radians radians
180 180 3
Degree-Radian Conversion
180To convert radians to degrees, multiply by .
radians radians
To convert degrees to radians, multiply by .180
Arc Length Formula (Radian Measure)
If is a central angle in a circle of radius , and if is measured in
radians, then the length of the intercepted arc is given by
.
r
s
s r
Arc Length Formula (Degree Measure)
If is a central angle in a circle of radius , and if is measured in
degrees, then the length of the intercepted arc is given by
.180
r
s
rs
Example Perimeter of a Pizza Slice
Find the perimeter of a 30 slice of a large 8 in. radius pizza.
Example Perimeter of a Pizza Slice
Find the perimeter of a 30 slice of a large 8 in. radius pizza.
Let equal the arc length of the pizza's curved edge.
8 30 2404.2 in.
180 1808 in. 8 in. in.
20.2 in.
s
s
P s
P
Angular and Linear Motion
Angular speed is measured in units like revolutions per minute.
Linear speed is measured in units like miles per hour.
Quick Review Solutions
1. Solve for x.
x
3
2
2. Solve for x.
6
3
x
13x
3 3x
Standard Position
An acute angle θ in standard position, with one ray along the positive x-axis and the other extending into the first quadrant.
Trigonometric Functions
Let be an acute angle in the right ABC. Then
sine sin cosecant csc
cosine cos secant sec
tangent tan cotangent cot
opp hyp
hyp opp
adj hyp
hyp adj
opp adj
adj opp
Example Evaluating Trigonometric Functions of 45º
Find the values of all six trigonometric functions for an angle of 45º.
Example Evaluating Trigonometric Functions of 45º
Find the values of all six trigonometric functions for an angle of 45º.
1 2 2sin 45 0.707 csc 45 1.414
2 12
1 2 2cos 45 0.707 sec 45 1.414
2 12
1 1tan 45 1 cot 45 1
1 1
opp hyp
hyp opp
adj hyp
hyp adj
opp adj
adj opp
Example Evaluating Trigonometric Functions of 60º
Find the values of all six trigonometric functions for an angle of 60º.
Common Calculator Errors When Evaluating Trig Functions
Using the calculator in the wrong angle mode (degree/radians)
Using the inverse trig keys to evaluate cot, sec, and csc
Using function shorthand that the calculator does not recognize
Not closing parentheses
Example Solving a Right Triangle
A right triangle with a hypotenuse of 5 inches includes a 43 angle.
Find the measures of the other two angles and the lengths of the other
two sides.
Since it is a right triangle, one of the other angles is 90 .
That leaves 180 43 90 47 for the third angle.
Let equal the side length across from the 43 angle.
sin 47 so 3.45
Let equal
a
aa
b
the side length across from the 47 angle.
sin 47 so 3.75
bb
Example Evaluating Trigonometric Functions of 60º
3 2 2 3sin 60 0.866 csc60 1.155
2 33
1 2cos60 sec60 2
2 1
3 1 3tan 60 1.732 cot 60 0.577
1 33
opp hyp
hyp opp
adj hyp
hyp adj
opp adj
adj opp
Find the values of all six trigonometric functions for an angle of 60º.
Initial Side, Terminal Side
Positive Angle, Negative Angle
Coterminal Angles
Two angles in an extended angle-measurement system can have the same initial side and the same terminal side, yet have different measures. Such angles are called coterminal angles.
Example Finding Coterminal Angles
Find a positive angle and a negative angle that are coterminal
with 45 .
Add 360 : 45 360 405
Subtract 360 : 45 360 315
Example Finding Coterminal Angles
Find a positive angle and a negative angle that are coterminal
with .6
13Add 2 : 2
6 611
Subtract 2 : 26 6
Example Evaluating Trig Functions Determined by a Point in QI
Let be the acute angle in standard position whose terminal
side contains the point (3,5). Find the six trigonometric functions
of .
The distance from (3,5) to the origin is 34.
5 34sin 0.857 csc 1.166
534
3 34cos 0.514 sec 1.944
3345 3
tan cot3 5
Trigonometric Functions of any Angle
2 2
Let be any angle in standard position and let ( , ) be any point on the
terminal side of the angle (except the origin). Let denote the distance from
( , ) to the origin, i.e., let . Then
si
P x y
r
P x y r x y
n csc ( 0)
cos sec ( 0)
tan ( 0) cot ( 0)
y ry
r y
x rx
r xy x
x yx y
Evaluating Trig Functions of a Nonquadrantal Angle θ
1. Draw the angle θ in standard position, being careful to place the terminal side in the correct quadrant.
2. Without declaring a scale on either axis, label a point P (other than the origin) on the terminal side of θ.
3. Draw a perpendicular segment from P to the x-axis, determining the reference triangle. If this triangle is one of the triangles whose ratios you know, label the sides accordingly. If it is not, then you will need to use your calculator.
4. Use the sides of the triangle to determine the coordinates of point P, making them positive or negative according to the signs of x and y in that particular quadrant.
5. Use the coordinates of point P and the definitions to determine the six trig functions.
Example Evaluating More Trig Functions
Find sin 210 without a calculator.
Example Evaluating More Trig Functions
Find sin 210 without a calculator.
An angle of 210 in standard position determines a 30 60 90 reference
triangle in the third quadrant. The lengths of the sides determines the
point ( 3, 1). The hypotenuese is 2.
sin 210 / 1/ 2
P r
y r
.
Example Using one Trig Ration to Find the Others
Find sin and cos , given tan 4 / 3 and cos 0.
Since tan is positive the terminal side is either in QI or QIII.
The added fact that cos is negative means that the terminal
side is in QIII. Draw a reference triangle with 5, -3,
and -4.
sin -
r x
y
4 / 5 and cos -3 / 5
Unit Circle
The unit circle is a circle of radius 1 centered at the origin.
Trigonometric Functions of Real Numbers
Let be any real number, and let ( , ) be the point corresponding to
when the number line is wrapped onto the unit circle as described above.
Then
1sin csc ( 0)
cos
t P x y
t
t y t yy
t x
1
sec ( 0)
tan ( 0) cot ( 0)
t xx
y xt x t yx y
Periodic Function
A function ( ) is if there is a positive number such that
( ) ( ) for all values of in the domain of . The smallest such
number is called the of the function.
y f t c
f t c f t t f
c
periodic
period
The 16-Point Unit Circle
Quick Review Solutions
+,+, ,
+, ,+
State the sign (positive or negative) of the function in each quadrant.
1. sin
2. cot
Give the radian measure of the angle.
3. 150
,
5 /6
3 /4
4. 135
5. Find a transformation th
x
x
1
2
at will transform the graph of to
the vertgr icaph allyof 2 stretch by 2.
y x
y x
What you’ll learn about
The Basic Waves Revisited Sinusoids and Transformations Modeling Periodic Behavior with Sinusoids
… and why
Sine and cosine gain added significance when
used to model waves and periodic behavior.
Sinusoid
A function is a if it can be written in the form
( ) sin( ) where , , , and are constants
and neither nor is 0.
f x a bx c d a b c d
a b
sinusoid
Amplitude of a Sinusoid
The of the sinusoid ( ) sin( ) is | |.
Similarly, the amplitude of ( ) cos( ) is | |.
Graphically, the amplitude is half the height of the wave.
f x a bx c d a
f x a bx c d a
amplitude
Period of a Sinusoid
The of the sinusoid ( ) sin( ) is 2 / | | .
Similarly, the period of ( ) cos( ) is 2 / | | .
Graphically, the period is the length of one full cycle of the wave.
f x a bx c d b
f x a bx c d b
period
Example Horizontal Stretch or Shrink and Period
Find the period of sin and use the language of transformations2
to describe how the graph relates to sin .
xy
y x
Example Horizontal Stretch or Shrink and Period
Find the period of sin and use the language of transformations2
to describe how the graph relates to sin .
xy
y x
2The period is 4 . The graph of sin is a horizontal
1 22
stretch of sin by a factor of 2.
xy
y x
Frequency of a Sinusoid
The of the sinusoid ( ) sin( ) is | | / 2 .
Similarly, the frequency of ( ) cos( ) is | | / 2 .
Graphically, the frequency is the number of complete cycles the
wave completes in a un
f x a bx c d b
f x a bx c d b
frequency
it interval.
Example Combining a Phase Shift with a Period Change
Construct a sinusoid with period /3 and amplitude 4 that goes through (2,0).
Example Combining a Phase Shift with a Period Change
Construct a sinusoid with period /3 and amplitude 4 that goes through (2,0).
To find the coefficient of , set 2 / | | / 3 and solve for .
Find 6. Arbitrarily choose 6.
For the amplitude set | | 4. Arbitrarily choose 4.
The graph contains (2,0) so shift the function 2
x b b
b b
a a
units to the right.
4sin(6( - 2)) 4sin(6 -12).y x x
Graphs of Sinusoids
The graphs of sin( ( )) and cos( ( - )) (where 0 and
0) have the following characteristics:
amplitude = | | ;
2period = ;
| |
| |frequency = .
2When complared to the graphs of sin and
y a b x h k y a b x h k a
b
a
b
b
y a bx
cos , respectively,
they also have the following characteristics:
a phase shift of ;
a vertical translation of .
y a bx
h
k
Constructing a Sinusoidal Model using Time
1. Determine the maximum value and minimum value . The amplitude
-of the sunusoid will be , and the vertical shift will be .
2 22. Determine the period , the time interval of a single cy
M m A
M m M mA C
p
cle of the periodic
2function. The horizontal shrink (or stretch) will be .
3. Choose an appropriate sinusoid based on behavior at some given time .
For example, at time :
( ) cos( ( - )) attai
Bp
T
T
f t A B t T C
ns a maximum value;
( ) - cos( ( - )) attains a minimum value;
( ) sin( ( - )) is halfway between a minimum and a maximum value;
( ) - sin( ( - )) is halfway between a maximum and a minimum val
f t A B t T C
f t A B t T C
f t A B t T C
ue.
Quick Review
2
State the period of the function.
1. cos 4
12. sin
4Find the zeros and the vertical asymptotes of the function.
13.
11
4. 2 3
5. Tell whether 4 is odd, even, or neither.
y x
y x
xy
xx
yx x
y x
Quick Review Solutions
2
State the period of the function.
1. cos 4
12. sin
4Find the zeros and the vertical asymptotes of the function.
13.
/2
8
1; 1 1
14.
2 3
5. Tell whether 4 i
1; 3, 2
y x
y x
xy
xx
yx x
y x
x
x x
s odd, even, or neither. even
What you’ll learn about
The Tangent Function The Cotangent Function The Secant Function The Cosecant Function
… and whyThis will give us functions for the remaining trigonometric ratios.
Asymptotes of the Tangent Function
Zeros of the Tangent Function
Asymptotes of the Cotangent Function
Zeros of the Cotangent Function
The Secant Function
The Cosecant Function
Basic Trigonometry Functions
Quick Review Solutions
State the domain and range of the function.
1. ( ) -3sin 2
2. ( ) | | 2
Domain: , Range: 3,3
Domain: , Rang
3. ( ) 2cos3
e: 2,
Domain:
4. Describe t
, Range:
he behavior o
2,2
f
f x x
f x x
f x x
2
3
2
3- as .
5. Find and , given ( ) 3 and (
lim 0
3; 3
)
x
x
xy e x
f g g f f x x g x x
e
f g x g f x
What you’ll learn about
Combining Trigonometric and Algebraic Functions Sums and Differences of Sinusoids Damped Oscillation
… and why
Function composition extends our ability to model
periodic phenomena like heartbeats and sound waves.
Example Combining the Cosine Function with x2
2
Graph cos and state whether the function appears to be periodic.y x
Example Combining the Cosine Function with x2
2
Graph cos and state whether the function appears to be periodic.y x
The function appears to be periodic.
Example Combining the Cosine Function with x2
2Graph cos and state whether the function appears to be periodic.y x
Example Combining the Cosine Function with x2
2Graph cos and state whether the function appears to be periodic.y x
The function appears to not be periodic.
Sums That Are Sinusoids Functions
1 1 1 2 2 2
1 2 1 1 2 2
If sin( ( )) and cos( ( )), then
y sin( ( )) cos( ( )) is a
sinusoid with period 2 / | |.
y a b x h y a b x h
y a b x h a b x h
b
Example Identifying a Sinusoid
Determine whether the following function is or is not a sinusoid.
( ) 3cos 5sinf x x x
Example Identifying a Sinusoid
Determine whether the following function is or is not a sinusoid.
( ) 3cos 5sinf x x x
Yes, since both functions in the sum have period 2 .
Example Identifying a Sinusoid
Determine whether the following function is or is not a sinusoid.
( ) cos3 sin 5f x x x
Example Identifying a Sinusoid
Determine whether the following function is or is not a sinusoid.
( ) cos3 sin 5f x x x
No, since cos3 has period 2 / 3 and sin 5 has period 2 / 5.x x
Damped Oscillation
The graph of ( ) cos (or ( )sin ) oscillates between the
graphs of ( ) and - ( ). When this reduces the amplitude
of the wave, it is called . The factor ( ) is called
4. State the bearing that describes the direction NW (northwest).
5. State the amplitude and period of the sinusoid 3cos 2( 1).x
Quick Review Solutions
1. Solve for a.
a
3
23º 7.678
Quick Review Solutions
2. Find the complement of 47 .
3. Find the supplement of 47 .
4. State the bearing that
43
133
1describes the direction NW (northwest).
5. State the amplitude and period of the sinus
35
oid 3c
os 2( 1).
3, A p
x
What you’ll learn about
More Right Triangle Problems Simple Harmonic Motion
… and why
These problems illustrate some of the better-
known applications of trigonometry.
Angle of Elevation, Angle of Depression
An angle of elevation is the angle through which the eye moves up from horizontal to look at something above. An angle of depression is the angle through which the eye moves down from horizontal to look at something below.
Example Using Angle of Elevation
The angle of elevation from the buoy to the top of the Barnegat Bay lighthouse 130 feet above the surface of the water is 5º. Find the distance x from the base of the lighthouse to the buoy.
130
x
5º
Example Using Angle of Elevation
The angle of elevation from the buoy to the top of the Barnegat Bay lighthouse 130 feet above the surface of the water is 5º. Find the distance x from the base of the lighthouse to the buoy.
130
x
5º
130tan 5
1301485.9
tan 5The buoy is about 1486 feet from the base of the lighthouse.
x
x
Simple Harmonic Motion
A point moving on a number line is in if its
directed distance from the origin is given by either
sin or cos , where and are real numbers and 0.
The motion has
d
d a t d a t a
simple harmonic motion
frequency / 2 , which is the number of
oscillations per unit of time.
Example Calculating Harmonic Motion
A mass oscillating up and down on the bottom of a spring (assuming perfect elasticity and no friction or air resistance) can be modeled as harmonic motion. If the weight is displaced a maximum of 4 cm, find the modeling equation if it takes 3 seconds to complete one cycle.
Example Calculating Harmonic Motion
A mass oscillating up and down on the bottom of a spring (assuming perfect elasticity and no friction or air resistance) can be modeled as harmonic motion. If the weight is displaced a maximum of 4 cm, find the modeling equation if it takes 3 seconds to complete one cycle.
Assume the spring is at the origin of the coordinate system when 0 and
use the equation sin .
The maximum displacement is 4 cm, so 4.
One cycle takes 3 sec, so the period is 3 and the frequency i
t
d a t
a
s 1/3.
1 2Therefore, and .
2 3 32
Put this together and sin 4sin .3
d a t d t
Chapter Test
1. The point (-1, 3) is on the terminal side of an angle in standard position.
Give the smallest positive angle measure in both degrees and radians.
2. Evaluate sec without using a calculator.3
3
. Find all six trigonometric functions of in ABC.
5
C12
αA
B
Chapter Test
4. The point (-5,-3) is on the terminal side of angle . Evaluate
the six trigonometric functions for .
5. Use transformations to describe how the graph of the function
-2 -3sin - is related to the fy x
unction sin . Graph two periods.
6. State the amplitude, period, phase shift, domain and range for
( ) 1.5sin 2 - / 4 .
y x
f x x
Chapter Test
2
-1
7. Find the exact value of without using a calculator:
tan -1, 0 .
sin8. Describe the end behavior of ( ) .
9. Find an algebraic expression equivalent to tan cos .
10. From the top of a 150-
x
x x
xf x
xx
ft building Kana observes a car
moving toward her. If the angle of depression of the car
changes from 18 to 42 during the observation, how far
does the car travel?
1. The point (-1, 3) is on the terminal side of an angle in standard position.
Give the smallest posit
120
ive angle measure in both degrees and radians.
2. Evaluate s
2 / 3 radian
ec without us3
s
2
sin
ing a calculator.
3. Find all six trigonometric functions of in ABC.
5 /13 csc =13/5
cos =12/13 sec =13/12
tan 5 /12 cot =12/5
Chapter Test Solutions
5
C 12
αA
B
4. The point (-5,-3) is on the terminal side of angle . Evaluate
the six trigonometric functions for sin 3/ 34; csc = 34/3;
cos = 5/ 34; sec = 34/5; tan 3/ 5; cot
.
5. Use transformations
=5/3
to
describe how the graph of the function
-2 -3sin - is related to the function sin . Graph two peri
translation right units, vertical stretch by a factor of 3, reflected
across the
ods.
-axis, tranx
y x y x
6. State the amplitude, period, phase shift, domain and range for
( ) 1.5sin 2 - / 4 .
slation down 2 units.
A=1.5; p= ; ps= /8; domain: - , ; range: -1.5,1.5f x x
Chapter Test Solutions
Chapter Test Solutions
2
-1
7. Find the exact value of without using a calculator:
tan -1, 0 .
sin8. Describe the end behavior of ( ) .
9. Find an algebraic expression
3 /4
As | | , ( ) 0
equivalent to tan cos .-
1
x
x x
xf x
x f x
x
x
x
2
10. From the top of a 150-ft building Kana observes a car
moving toward her. If the angle of depression of the car
changes from 18 to 42 during the observation, how far