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VCE 11 Methods 2023

4.06 Square root functions

Worksheet
Key features
1

Consider the graph of y = \sqrt{ - x }:

As x approaches -\infty, what does y approach?

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2

Consider the graph of y = \sqrt{x}:

a

Describe the rate of increase of the function as x increases.

b

State the axes intercepts.

c

Does the function have an asymptote?

d

Does the function have a limiting value?

e

As x increases, what does y approach?

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3

Consider the function y = - \sqrt{x}.

a

Complete the table of values. Round any values to two decimal places if necessary.

b

Can the function values ever be positive?

x0123459
y
c

The graph of the function y = - \sqrt{x} is shown. Is y = - \sqrt{x} an increasing function or a decreasing function?

d

Describe the rate of decrease of the function as x increases.

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4

Consider the function y = \sqrt{ - x }.

a

Complete the table of values. Round any values to two decimal places if necessary.

x-5-4-3-2-10
y
b

The graph of y = \sqrt{ - x } is given.

Is y = \sqrt{ - x } an increasing function or a decreasing function?

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5

Consider the function y = \sqrt{x} + 3.

a

Can y ever be negative?

b

As x gets larger and larger, what value does y approach?

c

Determine the y-intercept of the curve.

d

How many x-intercepts does it have?

e

Sketch the graph.

6

Consider the function y = 2 \sqrt{x} + 3.

a

Is the function increasing or decreasing from left to right?

b

Is the function more or less steep than y = \sqrt{x} ?

c

What are the coordinates of the vertex?

d

Sketch the graph.

7

Consider the function y = - \dfrac{1}{2} \sqrt{x} + 2.

a

Is the function increasing or decreasing from left to right?

b

Is the function more or less steep than y = \sqrt{x} ?

c

What are the coordinates of the vertex?

d

Sketch the graph.

Domain and range
8

Consider the function y = \sqrt{ - x }.

a

State the domain of the function.

b

State the range of the function.

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-1
x
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9

Consider the function y = \sqrt{x}.

a

Complete the table of values. Round any values to two decimal places if necessary.

b

State the domain of the function.

c

State the range of the function.

x0123459
y
d

As x gets larger and larger, what value does y approach?

e

Sketch the graph of y = \sqrt{x}.

10

Consider the function y = - \sqrt{x}.

a

State the domain of the function.

b

State the range of the function.

11

The function y = \sqrt{x} has domain x \geq 0 and range y \geq 0.

What is the domain and range of y = \sqrt{x} - 2 ?

12

Consider the function y = \sqrt{x - 5}.

a

State the domain of the function.

b

State the range of the function.

c

Do the functions y = \sqrt{x} and y = \sqrt{x - 5} increase at the same rate?

13

Consider the function y = \sqrt{ - x } + 6.

a

What is the smallest possible function value?

b

State the domain of the function.

c

State the range of the function.

14

A square root function has a range of y \leq 0 and a domain of x \geq 0. Determine whether the following could be the equation of the function:

a

y = \sqrt{x}

b

y = - \sqrt{ - x }

c

y = - \sqrt{x}

d

y = 5 \sqrt{x}

e

y = - 5 \sqrt{x}

f

y = \sqrt{ - x }

15

For each of the following functions:

i

Sketch the graph

ii

State the domain

iii

State the range

a

f \left( x \right) = - \sqrt{x + 1}

b

f \left( x \right) = - 2 \sqrt{x + 5}

c

f \left( x \right) = 3 \sqrt{\left( \dfrac{1}{3} x\right)}

d

f \left( x \right) = - \dfrac{\sqrt{x}}{2} - 2

e

f \left( x \right) = \dfrac{\sqrt{x - 1}}{2} + 2

16

For each of the following functions:

i

State the domain of the function.

ii

State the range of the function.

iii

Sketch the graph.

a
y = - \sqrt{x} + 5
b
y = - 5 \sqrt{x}
c
y = - \sqrt{ - x }
d
y = \sqrt{x - 3} + 2
17

For which values of x do the following expressions evaluate to a real number?

a

\sqrt{ 7 x}

b

\sqrt{x - 2}

c

\sqrt{3 - x}

d

\sqrt{15 - 5 x}

e

\sqrt{x^{2} + 6}

18

Consider the function f \left( x \right) = \sqrt{x - 2} + 3. State the domain of the function using interval notation.

Transformations
19

The graph of y = \sqrt{x} has a vertex at \left(0, 0\right). By considering the transformations that have taken place, state the coordinates of the vertex of y = - \sqrt{x} + 3.

20

The graph of y = \sqrt{x} has been translated to the graph of y = \sqrt{x} - 4.

a

Describe the transformation that has occured on the original function.

b

Hence, sketch the graph of y = \sqrt{x} - 4.

21

Consider the graph of y = \sqrt{x} shown:

a
i

Sketch the curve after y = \sqrt{x} has been reflected about the y-axis.

ii

What is the equation of this new graph?

b
i

Sketch the curve after y = \sqrt{x} has been reflected about the x-axis.

ii

What is the equation of this new graph?

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22

Consider the function y = \sqrt{x}:

a

Describe how we can transform the graph of y = \sqrt{x} to get the graph of y = \sqrt{x - 4} + 3.

b

Hence, sketch the graph of y = \sqrt{x - 4} + 3.

23

Sketch the curve y = 3 \sqrt{x - 2} + 3.

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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.AoS1.3

graphs of power functions f(x) = x^n for n=-2, -1, 1/3, 1/2, 1,2,3,4 and transformations of these graphs to the form y=a(x+b)^n+c

U1.AoS1.11

sketch by hand graphs of power functions f(x) = x^n for n=-2, -1, 1/3, 1/2, 1,2,3,4 and simple transformations of these, and identify any vertical or horizontal asymptotes

U1.AoS1.12

draw graphs of polynomial functions of low degree, simple power functions and simple relations that are not functions

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