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AustraliaVIC
VCE 11 Methods 2023

8.08 Tangent function

Worksheet
Graph of tan x
1

Consider the graph of y = \tan x for - 2 \pi \leq x \leq 2 \pi.

a

State the y-intercept of the graph.

b

State the period of the function.

c

State the equations of the vertical asymptotes on the domain 0 \leq x \leq 2\pi.

d

Does the graph of y=\tan x increase or decrease between any two successive vertical asymptotes?

e

If x \gt 0, find the least value of x for which \tan x = 0.

-2\pi
-\frac{3}{2}\pi
-1\pi
-\frac{1}{2}\pi
\frac{1}{2}\pi
1\pi
\frac{3}{2}\pi
2\pi
x
-4
-3
-2
-1
1
2
3
4
y
2

Consider the graph of y = \tan x for - 2 \pi \leq x \leq 2 \pi.

a

Select the word that best describes the graph:

A

Periodic

B

Decreasing

C

Even

D

Linear

b

Determine the range of y = \tan x.

c

As x increases, determine the equation of the next asymptote of the graph after x = \dfrac{7 \pi}{2}.

-2\pi
-\frac{3}{2}\pi
-1\pi
-\frac{1}{2}\pi
\frac{1}{2}\pi
1\pi
\frac{3}{2}\pi
2\pi
x
-4
-3
-2
-1
1
2
3
4
y
3

Consider the graph of y = \tan x for - 2 \pi \leq x \leq 2 \pi.

a

Determine the sign of \tan x for \\ \pi \leq x < \dfrac{3 \pi}{2}.

b
In which quadrant of a unit circle is angle x if \pi \leq x < \dfrac{3 \pi}{2}.
c

Determine the sign of \tan x for \\- \dfrac{\pi}{2} < x \leq 0.

d
In which quadrant of a unit circle is angle x if - \dfrac{\pi}{2} < x \leq 0.
e

Describe the function y = \tan x as odd, even or neither.

-2\pi
-\frac{3}{2}\pi
-1\pi
-\frac{1}{2}\pi
\frac{1}{2}\pi
1\pi
\frac{3}{2}\pi
2\pi
x
-4
-3
-2
-1
1
2
3
4
y
4

Consider the right triangle containing angle \theta and the graph of y=\cos \theta.

-2\pi
-\frac{3}{2}\pi
-1\pi
-\frac{1}{2}\pi
\frac{1}{2}\pi
1\pi
\frac{3}{2}\pi
2\pi
\theta
-1
1
y
a
As angle \theta increases from 0 to \dfrac{\pi}{2}, explain what happens to the value of the opposite side in the triangle.
b

Hence explain what happens to the value of \tan \theta as angle \theta increases from 0 to \dfrac{\pi}{2}, given that \tan \theta is defined as \dfrac{\text{opposite }}{\text{adjacent }}.

c

Express \tan \theta in terms of \sin \theta and \cos \theta.

d

Determine the values of \theta for which \cos \theta = 0, given - 2 \pi \leq \theta \leq 2 \pi.

e

Hence, state the values of \theta between - 2 \pi and 2 \pi for which \tan \theta is undefined.

f

Complete the table below.

\theta-2\pi-\dfrac{7\pi}{4}-\dfrac{5\pi}{4}-\pi-\dfrac{3\pi}{4}-\dfrac{\pi}{4}
\tan \theta
\theta0\dfrac{\pi}{4}\dfrac{3\pi}{4}\pi\dfrac{5\pi}{4}\dfrac{7\pi}{4}2\pi
\tan \theta
g

Hence sketch the graph of y = \tan \theta on the domain - 2 \pi \leq \theta \leq 2 \pi.

Vertical dilations
5

Consider the graph of y = a \tan x.

a

From the graph, determine the value of y when x=\dfrac{\pi}{4}.

b

If y=\tan x, determine the value of y when x=\dfrac{\pi}{4}.

c

Find the vertical dilation factor that must be applied to y = \tan x to obtain this graph.

d

Hence state the value of a.

-1\pi
-\frac{3}{4}\pi
-\frac{1}{2}\pi
-\frac{1}{4}\pi
\frac{1}{4}\pi
\frac{1}{2}\pi
\frac{3}{4}\pi
1\pi
x
-4
-3
-2
-1
1
2
3
4
y
6

Determine the equation for each of the following functions, given the equation is in the form y = a \tan x:

a
-\frac{3}{2}\pi
-1\pi
-\frac{1}{2}\pi
\frac{1}{2}\pi
1\pi
\frac{3}{2}\pi
x
-4
-3
-2
-1
1
2
3
4
y
b
-\frac{3}{2}\pi
-1\pi
-\frac{1}{2}\pi
\frac{1}{2}\pi
1\pi
\frac{3}{2}\pi
x
-4
-3
-2
-1
1
2
3
4
y
c
-\frac{3}{2}\pi
-1\pi
-\frac{1}{2}\pi
\frac{1}{2}\pi
1\pi
\frac{3}{2}\pi
x
-4
-3
-2
-1
1
2
3
4
y
d
-\frac{3}{2}\pi
-1\pi
-\frac{1}{2}\pi
\frac{1}{2}\pi
1\pi
\frac{3}{2}\pi
x
-4
-3
-2
-1
1
2
3
4
y
7

On the same set of axes, sketch the graphs of y = \tan x and y = \dfrac{1}{2} \tan x, on the domain -2\pi \leq x \leq 2\pi.

8

On the same set of axes, sketch the graphs of y = 5 \tan x and y = - 4 \tan x, on the domain -\pi \leq x \leq \pi.

9

On the same set of axes, sketch the graphs of the functions f \left( x \right) = - \dfrac{1}{2} \tan x and \\g \left( x \right) = 2 \tan x, on the domain -\pi \leq x \leq \pi.

Horizontal dilations
10

Consider functions of the form y=\tan bx.

a

Complete the table identifying the period of the function when b = 1, 2, 3, 4.

b

State the period of y = \tan b x.

c

As the value of b increases, describe the effect on the period of y=\tan b x.

FunctionPeriod
\tan x\pi
\tan 2x
\tan 3x
\tan 4x
11

Consider the function y = \tan 3x.

a

Complete the tables of values:

x-\dfrac{2\pi}{3}-\dfrac{7\pi}{12}-\dfrac{\pi}{2}-\dfrac{5\pi}{12}-\dfrac{\pi}{3}-\dfrac{\pi}{4}-\dfrac{\pi}{6}-\dfrac{\pi}{12}
\tan 3x
x0\dfrac{\pi}{12}\dfrac{\pi}{6}\dfrac{\pi}{4}\dfrac{\pi}{3}\dfrac{5\pi}{12}\dfrac{\pi}{2}\dfrac{7\pi}{12}\dfrac{2\pi}{3}
\tan 3x
b

State the equations of the vertical asymptotes on the domain -\pi \leq x \leq \pi.

c

Find the interval between the asymptotes of y = \tan 3 x.

d

Hence, determine the period of y = \tan 3 x.

e

Write an expression for the period of y = \tan n x.

f

Sketch the graph of the function y = \tan 3 x on the domain -\pi \leq x \leq \pi.

12

Consider the function y = \tan 2 x.

a

Complete the table of values:

x-\pi-\dfrac{3\pi}{4}-\dfrac{\pi}{4}0\dfrac{\pi}{4}\dfrac{3\pi}{4}\pi
2x - \dfrac{3\pi}{2}
\tan 2x \text{Und}
b

Find the interval between the asymptotes of y = \tan 2 x.

c

Hence, determine the period of y = \tan 2 x.

d

Sketch the graph of y = \tan 2 x on the domain - \pi \leq x \leq \pi.

13

Consider the function f \left( x \right) = \tan 7 x.

a

Find the period of the function.

b

Find the equation of the first four asymptotes to the right of the origin.

14

If an asymptote of the function in the form g \left( x \right) = \tan b x is known to be x = \dfrac{\pi}{8}, find the equation of g \left( x \right).

15

Consider the graph of a function in the form y = \tan b x.

a

State the period of the function.

b

Hence, state the equation of the function.

-\frac{1}{6}\pi
\frac{1}{6}\pi
x
-4
-3
-2
-1
1
2
3
4
y
16

Consider the graph of f \left( x \right) = \tan \left( \alpha x\right), and the graph of g \left( x \right) = \tan \left( \beta x\right) displayed on the same coordinate axes:

-\frac{1}{2}π
-\frac{1}{4}π
\frac{1}{4}π
\frac{1}{2}π
x
-2
-1
1
2
y

Which is greater: \alpha or \beta? Explain your answer.

17

On the same set of axes, sketch the graphs of the functions f \left( x \right) = \tan \dfrac{1}{4} x and \\g \left( x \right) = \tan 4 x, on the domain - 2\pi \leq x \leq 2\pi.

18

The function f \left( x \right) has the form f \left( x \right) = \tan b x. If two neighbouring asymptotes of this function are known to have equations x = \dfrac{\pi}{12} and x = \dfrac{\pi}{4}, find the exact value of the \\x-intercept between the asymptotes.

19

A function in the form f \left( x \right) = \tan b x has adjacent x-intercepts at x = \dfrac{13 \pi}{6} and x = \dfrac{9 \pi}{4}.

a

Find the equation of the asymptote lying between the two x-intercepts.

b

Find the period of the function.

c

Determine the equation of the function.

20

The function f \left( x \right) = \tan 6 x is to be graphed on the interval \left[\dfrac{\pi}{12}, \dfrac{5 \pi}{12}\right].

a

Find the period of the function f \left( x \right) = \tan 6 x.

b

Find the equations of the asymptotes of the function that occur on this interval.

c

Find the x-intercepts of the function that occur on this interval.

d

Hence sketch the function f \left( x \right) = \tan 6 x on the given interval.

Horizontal translations
21

Consider the graph of f \left( x \right) = \tan x and three points A\left(0, 0\right), B\left(\dfrac{\pi}{4}, 1\right) and C\left(\dfrac{\pi}{2}, 0\right).

-1\pi
-\frac{5}{6}\pi
-\frac{2}{3}\pi
-\frac{1}{2}\pi
-\frac{1}{3}\pi
-\frac{1}{6}\pi
\frac{1}{6}\pi
\frac{1}{3}\pi
\frac{1}{2}\pi
\frac{2}{3}\pi
\frac{5}{6}\pi
1\pi
x
-3
-2
-1
1
2
3
y
a

If f \left( x \right) undergoes a transformation to g \left( x \right) = \tan \left(x - \dfrac{\pi}{3}\right), state the coordinates of the following points after the transformation:

i

A

ii

B

iii

C

b

Describe the transformation of f \left( x \right) to g \left( x \right).

c

Hence, sketch the graph of g \left( x \right) = \tan \left(x - \dfrac{\pi}{3}\right) on the domain - \pi \leq x \leq \pi.

22

Consider the function y = \tan \left(x - \dfrac{\pi}{4}\right).

a

Complete the table with exact values for \tan \left(x - \dfrac{\pi}{4}\right):

x0\dfrac{\pi}{4}\dfrac{5\pi}{12}\dfrac{\pi}{2}\dfrac{7\pi}{12}\dfrac{11\pi}{12}\pi\dfrac{13\pi}{12}\dfrac{5\pi}{4}
\tan \left( x - \dfrac{\pi}{4} \right)
b

Sketch the graph of y = \tan \left(x - \dfrac{\pi}{4}\right) on the domain - 2\pi \leq x \leq 2\pi.

c

Describe the transformation that turns the graph of y = \tan x into the graph of \\y = \tan \left(x - h\right).

23

Consider the graph of a function in the form f \left( x \right) = \tan \left(x - h\right), where 0 \leq h < \pi.

a

If g\left(x\right) = \tan x, describe the transformation of g \left( x \right) to f \left( x \right).

b

State the equation of f \left( x \right).

-1\pi
-\frac{3}{4}\pi
-\frac{1}{2}\pi
-\frac{1}{4}\pi
\frac{1}{4}\pi
\frac{1}{2}\pi
\frac{3}{4}\pi
1\pi
x
-4
-3
-2
-1
1
2
3
4
y
24

Consider the function f \left( x \right) = \tan \left(x - \dfrac{\pi}{7}\right).

a

If g\left(x\right) = \tan x, describe the transformation of g \left( x \right) to f \left( x \right).

b

State the equations of the first four asymptotes of f \left( x \right) to the right of the origin.

25

On the same set of axes, sketch the graphs of f \left( x \right) = \tan x and g \left( x \right) = \tan \left(x - \dfrac{\pi}{2}\right) on the domain -2\pi \leq x \leq 2\pi.

26

The function f \left( x \right) = \tan \left(x - \dfrac{\pi}{6}\right) is to be graphed on the interval \left[\dfrac{2 \pi}{3}, \dfrac{8 \pi}{3}\right].

a

Find the equations of the asymptotes of the function that occur on this interval.

b

Find the x-intercepts of the function that occur on this interval.

c

Sketch the function f \left( x \right) = \tan \left(x - \dfrac{\pi}{6}\right) on the interval .

27

Consider the following functions of the form f\left(x\right)=\tan \left( x-h\right):

a

Sketch a graph of each of the functions on the domain -\pi \leq x \leq \pi.

i

p \left( x \right) = \tan \left(x - \dfrac{2 \pi}{3}\right)

ii

r \left( x \right) = \tan \left(x + \dfrac{4\pi}{3}\right)

iii

s \left( x \right) = \tan \left(x + \dfrac{\pi}{3}\right)

iv

r \left( x \right) = \tan \left(x - \dfrac{53 \pi}{3}\right)

b

Compare the graphs in part (a) and explain your answer.

28

Consider the graph of f \left( x \right) = \tan \left(x - \beta\right), where 0 \leq \beta < \pi, and g \left( x \right) = \tan \left(x - \alpha\right), where 0 \leq \alpha < \pi.

Determine whether the following statements are true or false:

a

\beta must be greater than \alpha as the function f(x) has a greater horizontal translation from the graph of y = \tan x.

b

\alpha must be greater than \beta as the function f(x) has a greater horizontal translation from the graph of y = \tan x.

-\frac{1}{4}\pi
\frac{1}{4}\pi
\frac{1}{2}\pi
\frac{3}{4}\pi
1\pi
x
-4
-3
-2
-1
1
2
3
4
y
29

Consider the graphs of the following functions and state whether or not the graph is the same as y = - \tan x:

a

y = - \tan \left(x + \dfrac{3 \pi}{4}\right)

b

y = - \tan \left(x + \pi\right)

c

y = - \tan \left(x + \dfrac{\pi}{2}\right)

d

y = - \tan \left(x + 2 \pi\right)

Mixed transformations
30

Determine whether the following statements regarding the graph of y = \tan x, are true or false:

a

Altering the period will alter the position of the vertical asymptotes.

b

A phase shift has the same effect as a horizontal translation.

31

The graph of y = \tan x is shown. Find the equation of the new graph after the following transformations:

a

Reflected over the y-axis and then translated vertically 3 units down.

b

Dilated vertically by a scale factor of 2 and translated horizontally \dfrac{\pi}{3} units to the left.

c

Translated horizontally by \dfrac{\pi}{3} units right and then dilated horizontally by a scale factor of \dfrac{1}{2}.

-1\pi
-\frac{3}{4}\pi
-\frac{1}{2}\pi
-\frac{1}{4}\pi
\frac{1}{4}\pi
\frac{1}{2}\pi
\frac{3}{4}\pi
1\pi
x
-4
-3
-2
-1
1
2
3
4
y
32

For each of the following functions:

i

Determine the y-intercept.

ii

Determine the interval between the vertical asymptotes of the function.

iii

Hence, state the period of the function.

iv

State the equation of the first asymptote of the function for x \geq 0.

v

State the equation of the first asymptote of the function for x \leq 0.

vi

Sketch the graph the function on the domain -\pi \leq x \leq \pi.

a

y = - \tan x

b

y = \tan \left(x + \dfrac{\pi}{3}\right)

c

y = \tan \left(\dfrac{x}{2}\right)

d

y = \tan \left( 3 \left(x + \dfrac{\pi}{4}\right)\right)

33

For each of the following functions:

i

Find the value of y when x = \dfrac{\pi}{4}.

ii

Determine the period of the function.

iii

Hence, state the interval between the asymptotes of the function.

iv

State the equation of the first asymptote of the function for x \geq 0.

v

State the equation of the first asymptote of the function for x \leq 0.

vi

Sketch the graph the function on the domain -\pi \leq x \leq \pi.

a

y = 5 \tan x + 3

b

y = 4 \tan 3 x

34

Describe how the graph of each of the following functions has been transformed from the function y = \tan x:

a

y = - 5 \tan x

b

y = 3\tan x + 2

c

y = \tan \left(3\left(x + \dfrac{\pi}{4}\right)\right)

d

y = \tan \left( 2 x - \dfrac{\pi}{4}\right)

35

Determine the following features for each of the given functions:

i

Period

ii

Phase shift

iii

Range

iv

Midline

a

y = 6 - 3 \tan \left(x + \dfrac{\pi}{3}\right)

b

y = - 4 \tan \left(\dfrac{1}{5}x + \dfrac{\pi}{20}\right)

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Outcomes

U1.AoS1.2

qualitative interpretation of features of graphs of functions, including those of real data not explicitly represented by a rule, with approximate location of any intercepts, stationary points and points of inflection

U1.AoS1.7

the effect of transformations of the plane, dilation, reflection in axes, translation and simple combinations of these transformations, on the graphs of functions

U2.AoS1.1

the unit circle, radians, arc length and sine, cosine and tangent as functions of a real variable

U2.AoS1.19

sketch by hand the unit circle, graphs of the sine, cosine and exponential functions, and simple transformations of these to the form Af(bx)+c , sketch by hand graphs of log_a(x) and the tangent function, and identify any vertical or horizontal asymptotes

U2.AoS1.4

symmetry properties, complementary relations and periodicity properties for sine, cosine and tangent functions

U2.AoS1.5

circular functions of the form y=Af(nx)+c and their graphs, where f is the sine, cosine or tangent function

U2.AoS1.14

the key features and properties of the circular functions sine, cosine and tangent, and their graphs, including any vertical asymptotes

U2.AoS1.20

draw graphs of circular, exponential and simple logarithmic functions over a given domain and identify and discuss key features and properties of these graphs, including any vertical or horizontal asymptotes

U2.AoS1.15

the effect of transformations of the plane on the graphs of sine, cosine, tangent and exponential functions

U2.AoS1.21

describe the effect of transformations of the plane on the graphs of the sine, cosine, tangent and exponential functions

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