Mathematics for IGCSE & O level - Pythagoras' Theorem And Trigonometry (Section 3 - No. 41)
Which of the following is a valid application of the cosine rule: a² = b² + c² - 2bc cos A?
Finding side a when sides b and c and angle A are known.
Finding angle A when sides a, b, and c are known.
Finding side b when sides a and c and angle A are known.
Finding angle B when sides a, b, and c are known.
คำอธิบาย
The cosine rule enables calculation of either a side or an angle given the appropriate information.