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Ch. 8 - Techniques of Integration
Hass - Thomas' Calculus 15th Edition
Hass15th EditionThomas' CalculusISBN: 9780137616077Non è quello che usi tu?Cambia libro di testo
Capitolo 8, Problema 8.6.59a

Centroid:
Find the centroid of the region cut from the first quadrant by the curve
y = 1/√(x + 1) and the line x = 3.

Guida verificata passo dopo passo
1
Identify the region bounded by the curve \(y = \frac{1}{\sqrt{x + 1}}\), the vertical line \(x = 3\), and the coordinate axes in the first quadrant. The region lies between \(x = 0\) and \(x = 3\), and above the \(x\)-axis.
Set up the integral for the area \(A\) of the region using the formula \(A = \int_0^3 y \, dx = \int_0^3 \frac{1}{\sqrt{x + 1}} \, dx\). This will give the total area under the curve from \(x=0\) to \(x=3\).
Find the coordinates of the centroid \((\bar{x}, \bar{y})\) using the formulas: \(\bar{x} = \frac{1}{A} \int_0^3 x y \, dx = \frac{1}{A} \int_0^3 x \frac{1}{\sqrt{x + 1}} \, dx\) and \(\bar{y} = \frac{1}{2A} \int_0^3 y^2 \, dx = \frac{1}{2A} \int_0^3 \left(\frac{1}{\sqrt{x + 1}}\right)^2 \, dx\).
Evaluate each integral separately: the area integral, the \(x\)-moment integral \(\int_0^3 x y \, dx\), and the \(y\)-moment integral \(\int_0^3 y^2 \, dx\). Use substitution if necessary, for example, let \(u = x + 1\) to simplify the integrals.
After computing the integrals, substitute the results back into the centroid formulas to find \(\bar{x}\) and \(\bar{y}\). These values give the coordinates of the centroid of the region.

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The region is defined by the curve y = 1/√(x + 1), the vertical line x = 3, and the coordinate axes in the first quadrant. Understanding the limits of integration and the shape of the region is crucial for setting up the correct integrals to find area and moments.
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