Evaluate the limit as x approaches 0 of (1 - cos x) / x.

Prepare for the DAY 2002A Limits Test with interactive quizzes, detailed explanations, and various study resources. Strengthen your understanding of limits concepts and ace your exam!

Multiple Choice

Evaluate the limit as x approaches 0 of (1 - cos x) / x.

Explanation:
Near zero, cos x can be approximated by its Taylor expansion: cos x ≈ 1 - x^2/2, so 1 - cos x ≈ x^2/2. Dividing by x gives (1 - cos x)/x ≈ x/2, which tends to 0 as x → 0. Therefore the limit is 0. Another way to see it is by L’Hôpital’s rule: differentiating top and bottom gives sin x, which tends to 0 as x → 0.

Near zero, cos x can be approximated by its Taylor expansion: cos x ≈ 1 - x^2/2, so 1 - cos x ≈ x^2/2. Dividing by x gives (1 - cos x)/x ≈ x/2, which tends to 0 as x → 0. Therefore the limit is 0. Another way to see it is by L’Hôpital’s rule: differentiating top and bottom gives sin x, which tends to 0 as x → 0.

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