Which of the following identities rewrites in a form involving that is particularly…

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

Problem

Which of the following identities rewrites

1-\cos x

in a form involving

\sin

that is particularly handy when evaluating limits as

x\to 0

? (a)

1-\cos x = \sin^{2}x

(b)

1-\cos x = \sec^{2}x-1

(c)

1-\cos x = 2\sin^{2}\left(\dfrac{x}{2}\right)

(d)

1-\cos x = 2\sin\left(\dfrac{x}{2}\right)