Question

How does the Pythagorean Theorem relate to trigonometric ratios? What is important to remember about coterminal angles and their trigonometric function values?

Answer 1

How Pythagoras theorem relates to Trigonometry ratios

For a right angled triangle ∆ABC,

Let a = hypothenus

b = opposite

c = adjacent

Sin²θ + Cos²θ = 1

Provided that a² + b² = c²

To prove this divide through by c²

Tongive

a²/c² + b²/c² = c²/c²

Sinθ = a/c , Cosθ = b/c

So, the above equation becomes

(Sinθ)² + (Cosθ)² = 1

Sin²θ + Cos²θ = 1

Coterminal Angles

Coterminal Angles are angles who share the same initial side and terminal sides.

Finding coterminal angles is as simple as adding or subtracting 360° or 2π to each angle, depending on whether the given angle is in degrees or radians.