👉 Learn how to evaluate the six trigonometric functions of a given angle. When given an angle we locate the angle on the ...

👉 Learn how to evaluate the cosine of an angle in radians using the sum/difference formulas. To do this, we first express the given angle as a sum or a difference of two (easy to evaluate) angles, ...

a missing side in a right-angled triangle when another side and an angle are known. a missing angle in a right-angled triangle when two sides are known. In these formulae, the Greek letter θ (theta) ...

Being able to identify which formula to use, sine or cosine, and when, is necessary to answer questions on this topic successfully. Check you are confident in how to use the sine and cosine rules.