IB Mathematics (HL)/Trigonometry
Topic 3: Core - Circular Functions and Trigonometry
Circular functions are based upon the unit circle.
Length of an Arc
The arc length of an arc with radius r and angle θ radians between the two lines between the centre of the circle and the arc endpoints equals r⋅θ.
This is merely a derivation from the circumference formula: The circumference of a circle equals 2πr, since 2π radians or 360 degrees is the angle of a full circle. l = θ r
Compound Angle Identities
Double Angle Identities
Sine and Cosine Rules and Triangle Areas
For any triangle with side lengths a, b and c, and internal angles A, B and C at the opposing corners, the following identites hold.
Area of a Triangle
The area of the triangle equals