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📏Trigonometry Calculator & Identities

Trigonometry Calculator & Identities
FunctionValueExact
Pythagorean Identities
  • sin²θ + cos²θ = 1
  • 1 + tan²θ = sec²θ
  • 1 + cot²θ = csc²θ
Double Angle
  • sin(2θ) = 2sinθcosθ
  • cos(2θ) = cos²θ - sin²θ
  • cos(2θ) = 2cos²θ - 1
  • cos(2θ) = 1 - 2sin²θ
Sum/Difference
  • sin(A±B) = sinAcosB ± cosAsinB
  • cos(A±B) = cosAcosB ∓ sinAsinB
  • tan(A±B) = (tanA±tanB)/(1∓tanAtanB)
Half Angle
  • sin(θ/2) = ±√((1-cosθ)/2)
  • cos(θ/2) = ±√((1+cosθ)/2)

Solve a triangle given 3 values (at least one side)

About

Calculate all 6 trigonometric functions for any angle. Reference common trigonometric identities. Solve triangles using the law of sines and cosines.

About This Tool

Free online trigonometry calculator. Compute all 6 trigonometric functions for any angle. Reference common identities (Pythagorean, double angle, sum/difference). Solve triangles using law of sines and cosines.

  • Free to use, no registration required
  • Works entirely in your browser
  • No data sent to servers
  • Accessible on desktop and mobile
Use Cases
  • Homework and assignments
  • Exam preparation
  • Classroom demonstrations
  • Research and analysis
  • Quick calculations
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