Rankwise

limx→0⁺ x log x = 0

The limit of x log x as x tends to 0⁺ is 0.

Proof

  1. Write x log x = log x ÷ (1/x), an ∞/∞ form.
  2. L'Hôpital: (1/x) ÷ (−1/x²) = −x.
  3. As x → 0⁺, −x → 0.

Standard limits

Questions students ask

What is the limit of x log x as x tends to 0⁺?

0.

How do you prove lim x→0⁺ x log x = 0?

Write x log x = log x ÷ (1/x), an ∞/∞ form. L'Hôpital: (1/x) ÷ (−1/x²) = −x. As x → 0⁺, −x → 0.

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