Fundamental Trigonometric Identities (7.1.1)

Question 1

• An identity is an equation that is true for all meaningful values of the variable(s) involved.

Answer 1

• An identity is an equation that is true for all meaningful values of the variable(s) involved.

Question 2

• Four basic trigonometric identities:
  
  • tan θ = (sin θ)/cos θ
  • cos^2 θ + sin^2 θ = 1 (the Pythagorean identity)
  • 1 + tan^2 θ = sec^2 θ
  • 1 + cot^2 θ = csc^2 θ

Answer 2

• Four basic trigonometric identities:
  
  • tan θ = (sin θ)/cos θ
  • cos^2 θ + sin^2 θ = 1 (the Pythagorean identity)
  • 1 + tan^2 θ = sec^2 θ
  • 1 + cot^2 θ = csc^2 θ