The Foundations of Trigonometry

Trigonometric identities are equations involving trigonometric functions that are true for every value of the variables involved. They are essential for simplifying expressions and solving complex equations in calculus and physics.

Core Identities to Remember

• Pythagorean Identity: sin²θ + cos²θ = 1
• Quotient Identity: tanθ = sinθ / cosθ
• Reciprocal Identities: cscθ = 1 / sinθ, secθ = 1 / cosθ, cotθ = 1 / tanθ

Pro Tip for Exams

When solving trig problems, always try to convert everything to sine and cosine first. This often reveals hidden simplifications. Use our scientific calculator to verify your final numerical results by switching between Degrees and Radians as needed.