Functions

Exponential and logarithmic functions

Types of exercises: exponential function, logarithmic function, exponential growth and decay, logarithmic scales in applications, exponential function - base, monotonicity, range, logarithmic function - base, point of the graph, zero, domain.

Exercises are drawn at random from a large bank - every click gives a different set.

Solved: 0 of 10

1

For which argument does the function take this value?

f(x) = 3 · log₉ x, f(x) = 9

2

Compute the value of the function

f(x) = −2 · 4ˣ, f(−3) = ?

3

Solve the problem using the definition of a logarithm

The sound level in decibels is L = 10 · log(I/I₀), where I is the sound intensity in W/m² and I₀ = 10⁻¹² W/m². The sound level of one sound is 40 dB and of another one 20 dB. How many times greater is the intensity of the first sound than the intensity of the second one?

4

Find the base a

The graph of the function f(x) = logₐ x, where a > 0 and a ≠ 1, passes through the point (1/25, −2).

5

Give the number of bacteria

The number of bacteria in a culture doubles every 10 minutes. At first there were 100 bacteria. How many bacteria will there be after 30 minutes?

6

Give the range of the function f

The function f is given by the formula f(x) = (1/2)ˣ + 9.

7

Compute the value of the function

f(x) = 6 · log₉ x, f(81) = ?

8

Compute the value of the function

f(x) = 5 · 10ˣ, f(5) = ?

9

Solve the problem using the definition of a logarithm

The Richter magnitude of an earthquake is R = log(A/A₀), where A is the amplitude of the earthquake in centimetres and A₀ = 10⁻⁴ cm. One earthquake had magnitude 4 and another one 2. How many times greater was the amplitude of the first one than the amplitude of the second one?

10

Give the zero of the function f

The function f is given by the formula f(x) = log₂ x − 4.

This address is one particular set - everyone who opens it gets exactly the same exercises. Copy the link from the address bar and send it to the class. You can generate a new set at the top of the page.

PhiBoard is a free online whiteboard for maths

These exercises are part of it. On the board itself you can plot a function, write a formula in LaTeX, or solve a problem together with a teacher or a friend - live, in the browser. Our app is completely free.

Create a free account
See what the board can do
PhiBoard

A modern, interactive board for study and work. Create, teach and collaborate - completely free.

PhiBoard

Tools

Capabilities

Knowledge base

Support

FAQ

Our mission

Contact

More

Our goalFor schoolsNewsOur coursesExercise bankWorksheets

Documents

TermsPrivacy policy

office@phiboard.com

Support the project

© 2026 PhiBoard. All rights reserved.

Online math whiteboardOnline tutoring whiteboardWhiteboard for teachersFunction graphs online

We Use Cookies

To improve the quality of our services, we use cookies. Cookies help us tailor our website to your preferences, analyze how you use the site, and provide a better user experience. By accepting cookies, you consent to their use for optimizing functionality and content on the site.

We use cookies to keep the site working and to improve it. Choose which ones you accept.

Exponential and logarithmic functions - exercises with solutions (Functions) | PhiBoard