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Superposition of two sinusoids calculator

Combine two waves that share one frequency into a single wave: an amplitude of 3 at 0° plus an amplitude of 4 at 90° gives an amplitude of 5. The phase lands in the right quadrant, and the frequency is never needed. Free in your browser.

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If you enter
Amplitude 1
3
Phase 1
0
Amplitude 2
4
Phase 2
90
You get
Phase unit
Degrees
Phasor x
3
Phasor y
4
Amplitude
5

When two pure tones, AC voltages, or forced oscillations share the same frequency, their sum is always another sinusoid at that frequency—only the amplitude and phase change. Students, audio engineers, and circuit designers need that combined amplitude and phase without expanding product-to-sum identities by hand for every pair of phasors. This superposition of two sinusoids calculator accepts the two amplitudes and phases, converts them to rectangular phasor components, adds those components, and returns the magnitude and atan2 phase of the resultant. The common angular frequency never has to be supplied: it factors out of the phasor picture and cancels from the amplitude and phase of the sum.

What same-frequency superposition means in phasor form

A real cosinusoid of fixed angular frequency ω can be written A cos(ωt + φ). In the phasor convention used throughout AC circuit analysis and introductory waves courses, that wave is represented by the complex number A e to the jφ, or equivalently by the rectangular pair (A cos φ, A sin φ). Adding two such waves that share the same ω is then exactly the vector sum of their phasors: the real parts add and the imaginary parts add.

If the first wave has amplitude A1 and phase φ1 and the second has amplitude A2 and phase φ2, the rectangular sum is Rx equals A1 cos φ1 plus A2 cos φ2 and Ry equals A1 sin φ1 plus A2 sin φ2. The combined amplitude R is the Euclidean length hypot(Rx, Ry), and the combined phase φ is the two-argument arctangent atan2(Ry, Rx), which places the result in the correct quadrant instead of the principal half-range of a naïve arctan of Ry over Rx.

Reconstructing the time-domain signal is immediate: the sum is R cos(ωt + φ) with the same ω you started with. Signed amplitudes are allowed; a negative A is equivalent to a positive magnitude with an extra π (or one hundred eighty degrees) of phase, matching textbook algebra. Phases may be any finite real number in degrees or radians and are not reduced to a principal interval on input, so a full-turn equivalent such as three hundred sixty degrees behaves like zero after conversion.

Because frequency is shared, beats and amplitude modulation that require two different frequencies are outside this landing and belong on separate tools.

Where adding two waves of one frequency helps

Introductory physics and AC circuits courses assign dozens of two-tone or two-voltage phasor drills every term; a live calculator that returns both combined amplitude and quadrant-correct phase lets learners check work without flipping cosine signs by hand. Exam generators and LMS plugins need a deterministic oracle that rejects non-finite junk and never invents a second frequency when the problem states pure mono-frequency superposition. Electrical engineering homework on series AC sources and Kirchhoff voltage loops reduces to the same phasor sum before impedance enters the model.

Content sites that rank for superposition of two sinusoids calculator benefit from a free browser path that matches the paid automation path on the identical pure module. Failed validation does not consume balance. Keep requests small, pin the rounded fields in tests, and you get reproducible combined amplitudes and phases for homework, lab keys, and edge workers without standing up complex-number libraries of your own.

Different-frequency beats, Fourier series of many harmonics, and full SPICE phasor nets remain separate search intents and stay on their own landings so this page stays focused on the two-wave same-frequency case.

Physics and waves homework checks

Students enter two same-frequency amplitudes and phases and verify the textbook combined amplitude and phase against the ordered phasor sum.

LMS and exam auto-grading

Mark mono-frequency superposition items with a deterministic oracle that returns a stable twelve-decimal amplitude and atan2 phase.

AC sources and coherent tones

Combine two coherent AC voltages or audio tones at one frequency in scripts without importing a full complex-analysis stack.

How do I add two sinusoids of the same frequency?

Send finite amplitudes A1, A2 and phases φ1, φ2 (degrees by default).

Do I need to supply the frequency ω?

No. When both waves share the same ω, frequency cancels from the combined amplitude and phase. The result is always another sinusoid at that same ω.

What form of sinusoid is assumed?

Cosine form A·cos(ωt+φ). Sine waves convert by a phase shift of −90° (or −π/2): A·sin(ωt+φ)=A·cos(ωt+φ−π/2).

What if the two waves cancel completely?

Combined amplitude is zero and phase is reported as zero so clients always receive a finite polar pair. That is a valid success, not an error.

What is the phase of 3 at 0° plus 4 at 90°?

The combined wave has an amplitude of 5 and a phase of 53.130102354156°. The calculator uses the two-argument arctangent, so the phase always falls in the correct quadrant.

Everything on this page is available programmatically. This section is for teams who want to wire it into their own systems; everyone else can just use the tool above.

POSThttps://api.kit.forhosting.com/trig/superpose-same-frequency

Prefer to automate it? One authenticated POST creates the task; the result comes back by webhook or a signed link. The same capability also runs here on the web, by email and from Telegram — and soon from our app too.

curl -X POST https://api.kit.forhosting.com/trig/superpose-same-frequency \
  -H "Authorization: Bearer $KIT_KEY" \
  -H "Content-Type: application/json" \
  -d '{"amplitude_1":3,"phase_1":0,"amplitude_2":4,"phase_2":90}'
{
  "amplitude_1": 3,
  "phase_1": 0,
  "amplitude_2": 4,
  "phase_2": 90
}
{
  "task_id": "tsk_a1b2c3d4e5f6a1b2c3d4e5f6",
  "type": "trig.superpose_same_frequency",
  "status": "queued",
  "_links": {
    "result": "/tasks/tsk_…/result"
  }
}

The API is asynchronous: the call returns a task_id immediately and the result arrives by webhook. Polling is capped at 1 req/s per task.

Per request$0.002

Published price — no tokens, no invented credits. A failed task is never charged.

HTTPCodeMeaning
401unauthorizedMissing or invalid API key.
402insufficient_balanceYour balance doesn't cover the task price.
404unknown_typeThat task type doesn't exist.
429rate_limitedToo many requests. Use the webhook instead of polling.

What same-frequency superposition means in phasor form

When the two phasors cancel completely, R is zero and this endpoint reports phase zero so clients always receive a finite polar pair.

Input contract, response fields, and validation

Absolute values larger than one trillion are rejected as out of published bounds. A short formula string restates the phasor-sum identity for display next to the answer. POST a JSON body with four required finite numbers: amplitude_1 and phase_1 for the first cosinusoid, amplitude_2 and phase_2 for the second. Optionally set phase_unit to degrees (the default) or radians so that both input phases and the primary reported phase use the same unit. Each amplitude may also arrive under the aliases a1, A1, or amp1 for the first wave and a2, A2, or amp2 for the second; phases accept phi1, phi_1, or phase1 and phi2, phi_2, or phase2. Missing fields, empty strings, and non-finite values fail with invalid_input naming the field. An unknown phase_unit string fails with a clear message that only degrees or radians are accepted; those validation failures are not billed. On success the body echoes the four inputs and the resolved phase_unit, then lists the rectangular phasor components phasor_x and phasor_y, the combined amplitude, the primary phase in the caller unit, and both phase_degrees and phase_radians for convenience. Classic classroom check: amplitude_1 equals three at phase zero degrees and amplitude_2 equals four at ninety degrees yields phasor components three and four, combined amplitude five, and phase arctangent of four over three, about fifty-three point one three degrees—the same three-four-five geometry as a right-triangle resultant. Pair the JSON with your own plotter if you need a time-domain sketch; this endpoint returns amplitude and phase only and does not emit samples or plots.

Where a same-frequency sinusoid superpose API earns its keep

Audio and vibration notebooks combine two coherent drivers at a shared tone before measuring constructive or destructive interference; calling a tiny parse API avoids importing a full symbolic package for four numbers.

What does the superposition of two sinusoids calculator cost?

The browser tool is free. API requests use prepaid KIT balance at $0.002 per successful call; invalid input is not billed.

Read the full KIT documentation →