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Trigonometric Equation Solver

Solve sin, cos and tan equations on any interval by robust numerical root-finding — results as multiples of π, radians and degrees, with interval presets for [0,2π], [−π,π], [0,4π] and [0°,360°].

Related tools

All Trigonometry tools →
Trigonometric Function GrapherPlot A·f(Bx − C) + D for sin, cos, tan, cot, sec and csc with the asymptotes drawn, plus amplitude, period, phase shift, midline, domain, range and key points.Trigonometric Identities CalculatorFrom one known function value and a quadrant, rebuild all six functions with the right signs, then check the Pythagorean, reciprocal, double-angle and half-angle identities.Absolute Value Equation SolverSolve absolute-value equations like |x+3| = 5, 3|x+2| = 12 or |x+1| = |x−3| with step-by-step case analysis and exact solutions.Cubic Equation SolverSolve ax³ + bx² + cx + d = 0 for all three roots (real and complex), with the discriminant, the nature of the roots and steps.Exponential Equation SolverSolve exponential equations of six types — basic, coefficient, linear exponent, two bases, quadratic-in-a^x and shifted — with logarithms and a full step-by-step solution.Linear Equation SolverSolve linear equations like 2x + 3 = 7, x/2 + 4 = 7 or 7x − 5 = 3x + 11 in one variable, with exact fractions and step-by-step working.Literal Equation SolverRearrange a formula to solve for any variable — e.g. A = pi*r^2 gives r = sqrt(A/pi) — with genuine symbolic isolation for linear, power and product forms.Logarithmic Equation SolverSolve logarithmic equations of six types — basic, linear, two logs, sum of logs, exponential and change of base — with step-by-step working, base e support, and extraneous-root rejection.

Open Trigonometric Equation Solver and you get an answer straight away, with no account to create. You will find it under Trigonometry, with Trigonometric Function Grapher and Trigonometric Identities Calculator for the neighbouring cases.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What does Trigonometric Equation Solver do?

Solve sin, cos and tan equations on any interval by robust numerical root-finding — results as multiples of π, radians and degrees, with interval presets for [0,2π], [−π,π], [0,4π] and [0°,360°].

When would I actually use this?

Solving a triangle from what you can actually measure, converting between degrees and radians, and checking an identity before using it.

What is the most common mistake?

Leaving the calculator in the wrong angle mode. Degrees and radians differ by a factor of about 57, and the answer is wrong without ever looking wrong.

How is Trigonometric Equation Solver different from Trigonometric Function Grapher?

They sit next to each other but answer different questions: Trigonometric Function Grapher is the one to open when you need it to plot A·f(Bx − C) + D for sin, cos, tan, cot, sec and csc with the asymptotes drawn, plus amplitude, period, phase shift, midline, domain, range and key points. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Trigonometric Identities Calculator is the closest one after this: From one known function value and a quadrant, rebuild all six functions with the right signs, then check the Pythagorean, reciprocal, double-angle and half-angle identities.

What else is worth having open alongside it?

Absolute Value Equation Solver and Cubic Equation Solver — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

The identities are the classical ones and the arithmetic is exact to double precision. The law-of-sines case with two sides and a non-included angle can have two valid triangles, and both are reported.

Further reading

All guides →
ExplainerThe Flat Pattern of a Cone Is a Sector, Not a CircleRoll a 50 mm cone 80 mm tall and its pattern is a 190.8° slice of a 94 mm circle. Flatten a nearly cylindrical lampshade and the pattern radius runs to 839 mm — the shallower the taper, the further away the apex.ExplainerA 1 % Drop Rate Does Not Mean One Hundred RunsAt 1 %, a hundred attempts give you 63.4 % — not certainty. Ninety per cent takes 230 attempts and ninety-nine takes 459, and more than a third of players are still empty-handed at a hundred.ExplainerFibonacci and the Golden RatioThe Fibonacci sequence adds each pair of terms to make the next; the ratio of neighboring terms homes in on the golden ratio φ ≈ 1.618. See how, and where the pattern turns up.ExplainerWhat Is a Z-Score? Standard Deviations Above the MeanA z-score is z = (x − μ) / σ — how many standard deviations a value sits from the mean. Learn how to compute it, read the standard normal curve, and turn it into a percentile.How-toHow to Find the Distance Between Two PointsUse the distance formula d = √((x₂−x₁)² + (y₂−y₁)²) to measure the straight-line distance between two points on a plane, with a worked example and the midpoint too.How-toHow to Calculate the Slope of a Line: Rise Over RunFind the slope of a line from two points with m = (y₂ − y₁) / (x₂ − x₁), and read what a positive, negative, zero, or undefined slope tells you.