A Level

MATHEMATICS · Multi correct · A Level · Mathematics · Trigonometry · Trigonometry

Problem

f(x)=\cos^2 x+\cos^2\left(x+\frac{\pi}{3}\right)-\cos x\cos\left(x+\frac{\pi}{3}\right)

is (1) an odd function (2) an even function (3) a periodic function (4)

f(0)=f(1)