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Trigonometric Addition Formulas

by Anonymous

Add two angles on the unit circle to verify the addition and double-angle formulas, then merge two waves into a single sine.

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About this app

An interactive trigonometry lesson that visualizes angle addition formulas on the unit circle. Explore how sin(α+β) is built from sinα·cosβ and cosα·sinβ, derive the double-angle identity by setting both angles equal, and combine a·sin and b·cos into one shifted sine wave.

Use cases

  • High school students studying trigonometric identities
  • Teachers demonstrating angle addition formulas
  • Learners exploring double-angle formulas visually
  • Students connecting trigonometry with wave functions

Features

  • Interactive α and β controls for visualizing sin(α+β)
  • Double-angle view showing sin 2θ = 2·sinθ·cosθ
  • Wave synthesis view combining a·sin and b·cos
  • Displays resulting amplitude √(a²+b²) and phase shift
  • Guided missions with reset and next controls