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PRACTICE / Small-angle approximations

Estimate an approximation’s error

A calculation replaces sin θ by θ at θ = 0.12 rad. Use sin θ ≈ θ − θ³/6.

Estimate (θ − sin θ)/θ to leading order.

Organize the givens & assumptions
  • θ = 0.12 rad
  • Use sin θ ≈ θ − θ³/6
  • Fractional difference is defined relative to θ

Small positive angle in radians. The denominator is explicitly θ; keep only the stated leading correction.

  1. A0.0002880.000288
  2. B0.120.12
  3. C0.00240.0024
  4. D0.0240.024

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