Rankwise

limx→0 (1 − cos x) / x = 0

The limit of (1 − cos x) / x as x tends to 0 is 0.

Proof

  1. (1 − cos x)/x = x × (1 − cos x)/x².
  2. The second factor tends to ½ and x tends to 0, so the limit is 0 × ½ = 0.

Standard limits

Questions students ask

What is the limit of (1 − cos x) / x as x tends to 0?

0.

How do you prove lim x→0 (1 − cos x) / x = 0?

(1 − cos x)/x = x × (1 − cos x)/x². The second factor tends to ½ and x tends to 0, so the limit is 0 × ½ = 0.

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