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Trigonometry Calculator

Calculate sin, cos, tan, and their inverses. Includes special angle value tables, identities, and the unit circle.

MATHEMATICS

The Trigonometry Calculator computes the values of sin, cos, tan, csc, sec, and cot for a given angle.

Supports degree and radian input, inverse functions (arcsin, arccos, arctan), a special angles table with exact values, 19 trigonometric identities, and a unit circle SVG visualization.

Trigonometry Calculator

Calculate sin, cos, tan, csc, sec, cot with special angle values and complete trigonometric identities.

Masukkan sudut (derajat atau radian) untuk mendapatkan semua 6 nilai fungsi trigonometri sekaligus.

Calculator information

How to use this calculator

  1. Select input unit: degrees (0-360°) or radians (0-2π).
  2. Enter the angle value, for example: 30, 45, 90, or pi/4 (the calculator parses pi automatically).
  3. Select a function: sin, cos, tan, csc, sec, cot, or inverse (arcsin, arccos, arctan).
  4. Press Calculate for the numeric result plus exact values for special angles (30°, 45°, 60°, etc.).
  5. View the SVG unit-circle visualization showing the angle position, coordinates (cos θ, sin θ), and quadrant.
  6. Check the table of 19 trigonometric identities for Pythagorean, double-angle, sum-angle, and half-angle formulas.
  7. Tip: For quick conversion, 1 rad = 57.2958° or π rad = 180°; use degrees for geometry/surveying, radians for calculus/physics.

Trigonometric Functions & Pythagorean Identities

sin²θ + cos²θ = 1 ; tan θ = sin θ / cos θ ; θ(rad) = θ(°) × π/180
  • Unit circle: x = cos θ, y = sin θ for a point at radius 1
  • csc θ = 1/sin θ, sec θ = 1/cos θ, cot θ = 1/tan θ
  • Special angles: sin 30°=1/2, sin 45°=√2/2, sin 60°=√3/2
  • Double angle: sin 2θ = 2 sin θ cos θ; cos 2θ = cos²θ - sin²θ
  • Sum angle: sin(A+B) = sin A cos B + cos A sin B

The domain of tan θ is undefined at θ = 90° + 180°k (where cos θ = 0).

Worked example: Calculate sin, cos, tan for θ = 60°

Given:
  • θ = 60° = π/3 rad
  • Special angle of the 30-60-90 triangle
Steps:
  1. Convert to radians: 60° × π/180 = π/3 ≈ 1.0472 rad.
  2. sin 60° = √3/2 ≈ 0.8660.
  3. cos 60° = 1/2 = 0.5.
  4. tan 60° = sin 60° / cos 60° = (√3/2)/(1/2) = √3 ≈ 1.7321.
  5. Verify Pythagorean: sin² + cos² = 3/4 + 1/4 = 1 ✓.

Result: sin 60° = √3/2 ≈ 0.866; cos 60° = 0.5; tan 60° = √3 ≈ 1.732.

Frequently asked questions

When should I use degrees vs. radians?
Degrees are more intuitive for everyday geometry, land surveying, navigation (GPS), and astronomy (RA/Dec). Radians are required for calculus because the derivative of sin x = cos x only holds in radians; they are also used for physics (harmonic motion, waves), engineering (Fourier analysis), and programming (Math.sin in JavaScript uses radians). Conversion: π rad = 180°.
How do I memorize special angle values?
The 'left hand' trick: count 1, 2, 3, 4 for angles 0°, 30°, 45°, 60°. sin θ = √(finger count)/2; for example, √1/2 = 1/2 for 30°. Or memorize the triangles: 30-60-90 (sides 1:√3:2) and 45-45-90 (sides 1:1:√2). From these, derive everything: sin 30° = 1/2, sin 45° = √2/2, sin 60° = √3/2.
What is the difference between trig and inverse trig functions?
Direct functions: sin θ → ratio (0-1 for acute angles). Inverse functions (arcsin, sin⁻¹, asin): ratio → angle. Because sin is not one-to-one, the range of arcsin is restricted to [-90°, 90°] and arccos to [0°, 180°] to keep the function well-defined. Applications: surveyors use arctan to calculate slope grade from rise/run ratios; arccos determines the angle between two vectors.
What are real-life applications of trigonometry?
Surveying & GIS - measuring mountain heights from elevation angle and distance (h = d × tan θ); architecture - roof and stair design; astronomy - stellar parallax; acoustics - sound waves; physics - projectile motion (R = v² sin 2θ / g); electronics - AC current analysis; computer graphics - sprite rotation; navigation - the haversine formula for distance between two GPS points.
Why is tan θ undefined at 90°?
Because tan θ = sin θ / cos θ, and cos 90° = 0, which causes division by zero. Graphically, tan has vertical asymptotes at θ = 90° + 180°k (e.g., 90°, 270°, etc.). As θ approaches 90° from the left, tan → +∞; from the right, tan → -∞. The calculator will show an error or 'undefined'. The same applies to sec θ and cot θ at angles where the denominator is zero.

Last updated: May 11, 2026