SINCOSTAN
Trigonometry that clicks — calculators, identities, and worked explanations for angles and waves.
From solving a right triangle and applying the laws of sines and cosines to converting degrees and radians, breaking down a sine wave, inverting a ratio, and checking an identity, SinCosTan pairs free hands-on calculators with clear, worked explanations. Understand the angle, not just the answer.
Trigonometry Calculators
Free tools for angles, triangles, and waves — right triangle solver, law of sines & cosines solver, degrees to radians converter, sine wave calculator, inverse trig calculator, and a trig function & identity calculator.
Right Triangle Calculator
Solve a right triangle from any two values using sine, cosine, tangent, and the Pythagorean theorem — every side, both acute angles, area, and perimeter.
Law of Sines & Cosines Calculator
Solve any triangle from an ASA, AAS, SAS, SSS, or SSA set. The tool picks the right law automatically and flags the ambiguous case.
Degrees to Radians Converter
Convert degrees and radians both ways, and read the quadrant, reference angle, and unit-circle coordinates (cos θ, sin θ).
Sine Wave Calculator
Break down y = A·sin(B(x − C)) + D into amplitude, period, frequency, phase shift, midline, max and min, and evaluate y at any x.
Inverse Trig Calculator
Find an angle from a ratio with arcsin, arccos, or arctan — the principal value in both degrees and radians.
Trig Function & Identity Calculator
Evaluate all six trig functions at any angle, with undefined values handled cleanly and the Pythagorean identity checked live.
Museum of Mathematics
Wander an immersive, richly illustrated collection — the story of trigonometry, the history of mathematics, the mathematicians who shaped the field, and the geometry and waves behind it all, each in its own gallery. Every entry, image, and fact is drawn from Wikipedia and Wikimedia Commons.
Tour the museum →From the Journal
Clear, worked guides on solving right triangles, SOHCAHTOA, the laws of sines and cosines, the unit circle, radians, graphing sine waves, and the identities worth knowing — reading to pair with the calculators above.
How to Solve a Right Triangle
A step-by-step method for finding every unknown side and angle in a right triangle using the trig ratios, inverse functions, and the Pythagorean theorem.
SOHCAHTOA Explained: The Trig Ratios Made Simple
SOHCAHTOA is a six-letter memory trick that hands you the three core trig ratios, and this guide shows what each piece means with a worked example.
Law of Sines vs Law of Cosines: Which One to Use
A practical guide to choosing between the Law of Sines and the Law of Cosines, with the deciding rules and two short worked examples using real numbers.
Reading the Unit Circle
A guided tour of the unit circle, showing why each point is (cos, sin), listing the key angles and their exact values, and explaining the quadrant signs.
What Are Radians, and Why Mathematicians Prefer Them
Radians are the circle's own natural angle unit, and this article defines them from arc length, shows both conversions, and explains why calculus insists on them.
Graphing Sine and Cosine Waves
Learn to read amplitude, period, phase shift, and vertical shift straight off a sine or cosine equation, then sketch the wave without plotting points.
Keep Learning
Plain-language explainers on the building blocks of trigonometry — the right triangle and the unit circle, the sine and cosine functions and their graphs, and the identities and applications that tie it all together — everything you need to go deeper with confidence.
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