<< Chapter < Page Chapter >> Page >

Section exercises

Verbal

The inverse of every logarithmic function is an exponential function and vice-versa. What does this tell us about the relationship between the coordinates of the points on the graphs of each?

Since the functions are inverses, their graphs are mirror images about the line y = x . So for every point ( a , b ) on the graph of a logarithmic function, there is a corresponding point ( b , a ) on the graph of its inverse exponential function.

Got questions? Get instant answers now!

What type(s) of translation(s), if any, affect the range of a logarithmic function?

Got questions? Get instant answers now!

What type(s) of translation(s), if any, affect the domain of a logarithmic function?

Shifting the function right or left and reflecting the function about the y-axis will affect its domain.

Got questions? Get instant answers now!

Consider the general logarithmic function f ( x ) = log b ( x ) . Why can’t x be zero?

Got questions? Get instant answers now!

Does the graph of a general logarithmic function have a horizontal asymptote? Explain.

No. A horizontal asymptote would suggest a limit on the range, and the range of any logarithmic function in general form is all real numbers.

Got questions? Get instant answers now!

Algebraic

For the following exercises, state the domain and range of the function.

f ( x ) = log 3 ( x + 4 )

Got questions? Get instant answers now!

h ( x ) = ln ( 1 2 x )

Domain: ( , 1 2 ) ; Range: ( , )

Got questions? Get instant answers now!

g ( x ) = log 5 ( 2 x + 9 ) 2

Got questions? Get instant answers now!

h ( x ) = ln ( 4 x + 17 ) 5

Domain: ( 17 4 , ) ; Range: ( , )

Got questions? Get instant answers now!

f ( x ) = log 2 ( 12 3 x ) 3

Got questions? Get instant answers now!

For the following exercises, state the domain and the vertical asymptote of the function.

f ( x ) = log b ( x 5 )

Domain: ( 5 , ) ; Vertical asymptote: x = 5

Got questions? Get instant answers now!

g ( x ) = ln ( 3 x )

Got questions? Get instant answers now!

f ( x ) = log ( 3 x + 1 )

Domain: ( 1 3 , ) ; Vertical asymptote: x = 1 3

Got questions? Get instant answers now!

f ( x ) = 3 log ( x ) + 2

Got questions? Get instant answers now!

g ( x ) = ln ( 3 x + 9 ) 7

Domain: ( 3 , ) ; Vertical asymptote: x = 3

Got questions? Get instant answers now!

For the following exercises, state the domain, vertical asymptote, and end behavior of the function.

f ( x ) = ln ( 2 x )

Got questions? Get instant answers now!

f ( x ) = log ( x 3 7 )

Domain: ( 3 7 , ) ;
Vertical asymptote: x = 3 7 ; End behavior: as x ( 3 7 ) + , f ( x ) and as x , f ( x )

Got questions? Get instant answers now!

h ( x ) = log ( 3 x 4 ) + 3

Got questions? Get instant answers now!

g ( x ) = ln ( 2 x + 6 ) 5

Domain: ( 3 , ) ; Vertical asymptote: x = 3 ;
End behavior: as x 3 + , f ( x ) and as x , f ( x )

Got questions? Get instant answers now!

f ( x ) = log 3 ( 15 5 x ) + 6

Got questions? Get instant answers now!

For the following exercises, state the domain, range, and x - and y -intercepts, if they exist. If they do not exist, write DNE.

h ( x ) = log 4 ( x 1 ) + 1

Domain: ( 1 , ) ; Range: ( , ) ; Vertical asymptote: x = 1 ; x -intercept: ( 5 4 , 0 ) ; y -intercept: DNE

Got questions? Get instant answers now!

f ( x ) = log ( 5 x + 10 ) + 3

Got questions? Get instant answers now!

g ( x ) = ln ( x ) 2

Domain: ( , 0 ) ; Range: ( , ) ; Vertical asymptote: x = 0 ; x -intercept: ( e 2 , 0 ) ; y -intercept: DNE

Got questions? Get instant answers now!

f ( x ) = log 2 ( x + 2 ) 5

Got questions? Get instant answers now!

h ( x ) = 3 ln ( x ) 9

Domain: ( 0 , ) ; Range: ( , ) ; Vertical asymptote: x = 0 ; x -intercept: ( e 3 , 0 ) ; y -intercept: DNE

Got questions? Get instant answers now!

Graphical

For the following exercises, match each function in [link] with the letter corresponding to its graph.

Graph of five logarithmic functions.

For the following exercises, match each function in [link] with the letter corresponding to its graph.

Graph of three logarithmic functions.

f ( x ) = log 1 3 ( x )

B

Got questions? Get instant answers now!

h ( x ) = log 3 4 ( x )

C

Got questions? Get instant answers now!

For the following exercises, sketch the graphs of each pair of functions on the same axis.

f ( x ) = log ( x ) and g ( x ) = 10 x

Got questions? Get instant answers now!

f ( x ) = log ( x ) and g ( x ) = log 1 2 ( x )

Graph of two functions, g(x) = log_(1/2)(x) in orange and f(x)=log(x) in blue.
Got questions? Get instant answers now!

f ( x ) = log 4 ( x ) and g ( x ) = ln ( x )

Got questions? Get instant answers now!

f ( x ) = e x and g ( x ) = ln ( x )

Graph of two functions, g(x) = ln(1/2)(x) in orange and f(x)=e^(x) in blue.
Got questions? Get instant answers now!

For the following exercises, match each function in [link] with the letter corresponding to its graph.

Graph of three logarithmic functions.

f ( x ) = log 4 ( x + 2 )

Got questions? Get instant answers now!

g ( x ) = log 4 ( x + 2 )

C

Got questions? Get instant answers now!

h ( x ) = log 4 ( x + 2 )

Got questions? Get instant answers now!

For the following exercises, sketch the graph of the indicated function.

f ( x ) = log 2 ( x + 2 )

Graph of f(x)=log_2(x+2).
Got questions? Get instant answers now!

f ( x ) = 2 log ( x )

Got questions? Get instant answers now!

f ( x ) = ln ( x )

Graph of f(x)=ln(-x).
Got questions? Get instant answers now!

g ( x ) = log ( 4 x + 16 ) + 4

Got questions? Get instant answers now!

g ( x ) = log ( 6 3 x ) + 1

Graph of g(x)=log(6-3x)+1.
Got questions? Get instant answers now!

h ( x ) = 1 2 ln ( x + 1 ) 3

Got questions? Get instant answers now!

For the following exercises, write a logarithmic equation corresponding to the graph shown.

Use y = log 2 ( x ) as the parent function.

The graph y=log_2(x) has been reflected over the y-axis and shifted to the right by 1.

f ( x ) = log 2 ( ( x 1 ) )

Got questions? Get instant answers now!

Use f ( x ) = log 3 ( x ) as the parent function.

The graph y=log_3(x) has been reflected over the x-axis, vertically stretched by 3, and shifted to the left by 4.
Got questions? Get instant answers now!

Use f ( x ) = log 4 ( x ) as the parent function.

The graph y=log_4(x) has been vertically stretched by 3, and shifted to the left by 2.

f ( x ) = 3 log 4 ( x + 2 )

Got questions? Get instant answers now!

Use f ( x ) = log 5 ( x ) as the parent function.

The graph y=log_3(x) has been reflected over the x-axis and y-axis, vertically stretched by 2, and shifted to the right by 5.
Got questions? Get instant answers now!

Technology

For the following exercises, use a graphing calculator to find approximate solutions to each equation.

log ( x 1 ) + 2 = ln ( x 1 ) + 2

x = 2

Got questions? Get instant answers now!

log ( 2 x 3 ) + 2 = log ( 2 x 3 ) + 5

Got questions? Get instant answers now!

ln ( x 2 ) = ln ( x + 1 )

x 2 .303

Got questions? Get instant answers now!

2 ln ( 5 x + 1 ) = 1 2 ln ( 5 x ) + 1

Got questions? Get instant answers now!

1 3 log ( 1 x ) = log ( x + 1 ) + 1 3

x 0.472

Got questions? Get instant answers now!

Extensions

Let b be any positive real number such that b 1. What must log b 1 be equal to? Verify the result.

Got questions? Get instant answers now!

Explore and discuss the graphs of f ( x ) = log 1 2 ( x ) and g ( x ) = log 2 ( x ) . Make a conjecture based on the result.

The graphs of f ( x ) = log 1 2 ( x ) and g ( x ) = log 2 ( x ) appear to be the same; Conjecture: for any positive base b 1 , log b ( x ) = log 1 b ( x ) .

Got questions? Get instant answers now!

Prove the conjecture made in the previous exercise.

Got questions? Get instant answers now!

What is the domain of the function f ( x ) = ln ( x + 2 x 4 ) ? Discuss the result.

Recall that the argument of a logarithmic function must be positive, so we determine where x + 2 x 4 > 0 . From the graph of the function f ( x ) = x + 2 x 4 , note that the graph lies above the x -axis on the interval ( , 2 ) and again to the right of the vertical asymptote, that is ( 4 , ) . Therefore, the domain is ( , 2 ) ( 4 , ) .

Got questions? Get instant answers now!

Use properties of exponents to find the x -intercepts of the function f ( x ) = log ( x 2 + 4 x + 4 ) algebraically. Show the steps for solving, and then verify the result by graphing the function.

Got questions? Get instant answers now!

Questions & Answers

Ayele, K., 2003. Introductory Economics, 3rd ed., Addis Ababa.
Widad Reply
can you send the book attached ?
Ariel
?
Ariel
What is economics
Widad Reply
the study of how humans make choices under conditions of scarcity
AI-Robot
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn Reply
U(x,y) = (x×y)1/2 find mu of x for y
Desalegn
what is ecnomics
Jan Reply
this is the study of how the society manages it's scarce resources
Belonwu
what is macroeconomic
John Reply
macroeconomic is the branch of economics which studies actions, scale, activities and behaviour of the aggregate economy as a whole.
husaini
etc
husaini
difference between firm and industry
husaini Reply
what's the difference between a firm and an industry
Abdul
firm is the unit which transform inputs to output where as industry contain combination of firms with similar production 😅😅
Abdulraufu
Suppose the demand function that a firm faces shifted from Qd  120 3P to Qd  90  3P and the supply function has shifted from QS  20  2P to QS 10  2P . a) Find the effect of this change on price and quantity. b) Which of the changes in demand and supply is higher?
Toofiq Reply
explain standard reason why economic is a science
innocent Reply
factors influencing supply
Petrus Reply
what is economic.
Milan Reply
scares means__________________ends resources. unlimited
Jan
economics is a science that studies human behaviour as a relationship b/w ends and scares means which have alternative uses
Jan
calculate the profit maximizing for demand and supply
Zarshad Reply
Why qualify 28 supplies
Milan
what are explicit costs
Nomsa Reply
out-of-pocket costs for a firm, for example, payments for wages and salaries, rent, or materials
AI-Robot
concepts of supply in microeconomics
David Reply
economic overview notes
Amahle Reply
identify a demand and a supply curve
Salome Reply
i don't know
Parul
there's a difference
Aryan
Demand curve shows that how supply and others conditions affect on demand of a particular thing and what percent demand increase whith increase of supply of goods
Israr
Hi Sir please how do u calculate Cross elastic demand and income elastic demand?
Abari
Got questions? Join the online conversation and get instant answers!
Jobilize.com Reply

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Algebra and trigonometry. OpenStax CNX. Nov 14, 2016 Download for free at https://legacy.cnx.org/content/col11758/1.6
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Algebra and trigonometry' conversation and receive update notifications?

Ask