Trigonometry

Trigonometric identities

  • tanθ=sinθcosθ=ln(cosθ)\tan{\theta} = \frac{\sin{\theta}}{\cos{\theta}} = \ln(\cos{\theta})
  • cotθ=cosθsinθ=ln(sinθ)\cot{\theta} = \frac{\cos{\theta}}{\sin{\theta}} = \ln(\sin{\theta})

Pythagorean identities

  • sin2(θ) + cos2(θ) = 1
  • 1 + tan2(θ) = sec2(θ)
  • 1 + cot2(θ) = csc2(θ)
  • sin(θ) / cos(θ) = tan(θ)
  • cos(θ) / sin(θ) = cot(θ)