What is it?
The Trigonometry Calculator gives sin, cos, tan and cot of an Angle in Degrees or Radians, and inverse values (asin, acos, atan). For sec and cosec, take 1 ÷ cos and 1 ÷ sin.
Who is it for?
Students learning sin, cos and tan, and anyone finding heights and slopes from angles.
How to use it
- Type the Angle and choose the Unit.
- For inverse functions, type the Value for inverse (asin, acos, atan).
Common questions
- tan 90° is shown as not defined (infinite), because it divides by cos 90° = 0. The same goes for cot 0°.
- asin and acos need values between −1 and 1. asin(2) has no answer.
- Inverse functions give one angle, but there may be others: sin 30° = sin 150° = 0.5.
Exact values to remember
- sin 30° = 1/2, sin 45° = √2/2 ≈ 0.7071, sin 60° = √3/2 ≈ 0.8660.
- cos is the same values in reverse: cos 60° = 1/2.
- tan 45° = 1.
Uses: heights from angles (tree or building height = distance × tan of the angle up), slopes and ramps, and physics.
Worked example
Standing 20 m from a tree, the top is at 35° up: height ≈ 20 × tan 35° ≈ 14 m (plus your eye height).
Errors and how to fix them
- asin or acos shows —: inverse values must be between −1 and 1.
Open the tool: Trigonometry Calculator
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Questions, or an error not listed here?
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