This circle has the centre at the origin and a radius of 1 unit. The point P can move around the circumference of the circle. At point P the x -coordinate is cos θ and the y -coordinate is sin θ.

GCSE Edexcel Trigonometry - Edexcel Trigonometric graphs - Higher The three trigonometric ratios; sine, cosine and tangent are used to calculate angles and lengths in right-angled triangles. The ...