93.0k views
4 votes
Use your calculator to find the length of the arc from t = 0 to t = 2 of x = t3 + 2, y = 1 - t2 .

I got 9.07, please confirm. Thank you so much!

User Krosshj
by
7.8k points

1 Answer

1 vote

Explanation:

Using arc length formula for parametric equations:

L = ∫ₐᵇ √((dx/dt)² + (dy/dt)²) dt

L = ∫₀² √((3t²)² + (-2t)²) dt

L = ∫₀² √(9t⁴ + 4t²) dt

L = ∫₀² t√(9t² + 4) dt

If u = 9t² + 4, then du = 18t dt, or 1/18 du = t dt.

When t = 0, u = 4. When t = 2, u = 40.

L = 1/18 ∫₄⁴⁰ √u du

L = 1/18 (⅔ u^(³/₂)) |₄⁴⁰

L = 1/27 (u√u)|₄⁴⁰

L = 1/27 (40√40 − 4√4)

L ≈ 9.07

Your answer is correct!

User Jatinder Pal
by
7.7k points