Fourier Series and Transforms
Like Duolingo, but for Fourier Series and Transforms. Tomo turns the whole topic into a game you play five minutes a day, until it actually sticks.
For the part of you with thirty open tabs that never became anything.
21 levels across 3 sections, about 42 minutes end to end, roughly 8 days at five minutes a day. It moves through Decomposing Periodic Signals, Spectra and Generalized Systems, and Continuous and Discrete Transforms. It starts from scratch.
Free forever · No credit card · iPhone & Android

Key ideas in Fourier Series and Transforms
- Fourier series constructs periodic waves using only whole-number multiples of the base frequency
- A 100 Hz periodic wave requires harmonic components at 100 Hz, 200 Hz, 300 Hz, etc.
- Non-integer frequencies destroy the wave's strict periodicity over the original interval
- The first harmonic sets the primary repetition period of the wave
- Higher harmonics oscillate much faster, adding sharp corners and fine details
- Without high harmonics, sharp waveforms like square waves appear smoothed and rounded
- The constant a0 term in a Fourier series measures the net average value over one full cycle
- A waveform centered symmetrically around zero has zero net area per cycle and thus an a0 of zero
- Shifting a waveform vertically up or down alters only the a0 term
- Sinusoids of different harmonic frequencies multiply and integrate to zero over a shared period
- Only the matching harmonic produces a non-zero net area during integration
- Euler's formula begins by pairing the raw signal with a specific trial sine or cosine
- Multiplying the two functions highlights correlation at that exact frequency
- Integrating over the cycle sums the total correlation, which is then scaled to yield the coefficient
- A physical period of length 2L replaces the default 2π period by setting the half-period L
- The angle x becomes (n*pi*x)/L to map real spatial or temporal units to radians
You've tried the other tabs
Thirty open tabs. Four facts you actually kept.
You watched. You nodded. By Sunday it was gone.
One answer, then back to scrolling.
Eight weeks. You meant to finish. You didn't.
Tomo gives Fourier Series and Transforms the Duolingo treatment: levels, streaks, and quick quizzes that test what you just learned. That game loop is what the tabs above never had, so it's the one you actually finish.
Here's what playing it feels like
A real question from this course. Take your best guess.
If you want to build a repeating 100 Hz wave, which set of frequencies will you combine?
Get it right to open this lesson and 20 more in the app.
Where Fourier Series and Transforms takes you
Deconstruct complex signals and equations into pure sinusoidal components. Master harmonic analysis, boundary value problems, and continuous and discrete transforms for engineering applications.
- 1
Decomposing Periodic Signals
- Building Waves from Pure Harmonics
- Symmetry, Convergence, and Calculus
- 2
Spectra and Generalized Systems
- Complex Exponentials and Harmonic Spectra
- Orthogonal Functions and Sturm-Liouville Systems
- 3
Continuous and Discrete Transforms
- The Fourier Integral for Transients
- The Continuous Fourier Transform
- Discrete Fourier Analysis and Computation
3 sections · 7 units · 21 levels. Built to play, not to enroll.
You pick the voice
Fourier Series and Transforms is taught in the The Bestie style: your friend who just gets it. Want a different feel? In the app you can spin up the same topic in any of Tomo's teaching styles. Same facts, totally different vibe.
More Math on Tomo
Waves, Heat, and Hidden Patterns
Master the art of breaking complex signals into simple waves and solving the equations that describe how heat spreads and strings vibrate. Move beyond basic calculus to see the mathematical harmony in physical systems.
Calculus: The Mathematics of Change
Bridge the gap between algebra and higher mathematics by mastering the logic of limits, derivatives, and integrals. This course prepares you for the rigors of College Calculus II by focusing on the 'why' behind the formulas.
Precalculus Trigonometry
Bridge the gap between triangle geometry and continuous waves. Learn how sine, cosine, and tangent power circular motion, periodic graphing, and algebraic identities for advanced math.
Algebra for Functions and Modeling
Move beyond basic arithmetic to master the language of functions, complex systems, and the mathematical models that describe the real world.
Algebra: From Equations to Functions
Bridge the gap between basic arithmetic and advanced mathematical modeling. Learn to manipulate complex expressions, solve systems of constraints, and visualize the hidden curves that define our world.
Pre-calculus Basics
Bridge the gap between algebra and calculus by mastering the behavior of shapes and numbers. Learn how to predict patterns and understand the math of change.
Start Fourier Series and Transforms today.
Download Tomo, search Fourier Series and Transforms, and play your first lesson in under a minute.