Cosine Calculator

Compute cos(theta) instantly with degree or radian inputs.

Angle in radians
1.04719755
cos(theta)
0.50000000
sin²(theta)+cos²(theta)
1.00000000

Quick reference

  • Common value checks: cos(0°)=1, cos(60°)=0.5, cos(90°)=0.
  • Cosine is an even function, so cos(-theta) equals cos(theta).
  • Use radians when working with calculus or most programming APIs.
  • Identity check should be near 1.0; tiny drift comes from floating-point precision.

⚠️For educational and informational purposes only. Verify with a qualified professional.

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