Rankwise

limx→0 tan⁻¹x / x = 1

The limit of tan⁻¹x / x as x tends to 0 is 1.

Proof

  1. Put θ = tan⁻¹x, so x = tan θ and θ → 0.
  2. tan⁻¹x/x = θ/tan θ, which tends to 1.

Standard limits

Questions students ask

What is the limit of tan⁻¹x / x as x tends to 0?

1.

How do you prove lim x→0 tan⁻¹x / x = 1?

Put θ = tan⁻¹x, so x = tan θ and θ → 0. tan⁻¹x/x = θ/tan θ, which tends to 1.

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