Which of the following expressions is identically equal to 1 for every real value of ?

MATHEMATICS · Single correct · A Level · Mathematics · Trigonometry · Trigonometry

Problem

Which of the following expressions is identically equal to 1 for every real value of xx? (a) tan⁡2x+1\tan^2 x + 1 (b) sin⁡2x−cos⁡2x\sin^2 x - \cos^2 x (c) sin⁡2x+cos⁡2x\sin^2 x + \cos^2 x (d) sin⁡x+cos⁡x\sin x + \cos x

Related theory

Browse the problem library