AS/A2 Pure 2 Pure 3

P1 Topic 3: Trigonometry
Unit circle definitions 2
More than one angle can have the same sine value, for example, if sin x = 0.5 then x could be 30° or 150°. These diagrams show how the circle definition of trigonometrical functions causes this to happen. (Note that in these diagrams, distances indicated by the red arrows to the left or downward should imply a negative value for the trigonometrical function.)

Sine	Cosine
Please enable Java for an interactive construction (with Cinderella).	Please enable Java for an interactive construction (with Cinderella).

Tangent

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Summary The sine, cosine and tangent functions are valid for all angles from 0° to 360°, and beyond. The sine and cosine functions have values between -1 and 1. The tangent function can take all values. Cinderella interactive geometry.