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Use the Midpoint Rule with
n=5 to estimate the volume obtained by rotating about the y-axis the region under the curve
y=√(1+x^3),
0\leq x\leq 1.

2 Answers

3 votes
The answer your looking for is right above my
User Alexandre  Rozier
by
8.1k points
2 votes

To estimate the volume using the Midpoint Rule with
\displaystyle n=5, we need to divide the interval
\displaystyle 0\leq x\leq 1 into
\displaystyle n subintervals of equal width. Since
\displaystyle n=5, each subinterval will have a width of
\displaystyle \Delta x=(1-0)/(5)=(1)/(5).

Now, let's calculate the volume using the Midpoint Rule. The formula for the volume obtained by rotating about the y-axis is:


\displaystyle V\approx 2\pi \sum _(i=1)^(n)y_(i)\Delta x

where
\displaystyle y_(i) represents the value of the function
\displaystyle y=\sqrt{1+x^(3)} evaluated at the midpoint of each subinterval.

First, let's find the midpoints of the subintervals. Since the width of each subinterval is
\displaystyle \Delta x=(1)/(5), the midpoint of the
\displaystyle i-th subinterval is given by:


\displaystyle x_(i)=(\Delta x)/(2)+\left( i-(1)/(2)\right) \Delta x=(1)/(10)+\left( i-(1)/(2)\right) (1)/(5)

Substituting
\displaystyle x_(i) into the function
\displaystyle y=\sqrt{1+x^(3)}, we obtain:


\displaystyle y_(i)=\sqrt{1+\left( (1)/(10)+\left( i-(1)/(2)\right) (1)/(5)\right) ^(3)}

Now, we can calculate the approximate volume using the Midpoint Rule:


\displaystyle V\approx 2\pi \sum _(i=1)^(5)y_(i)\Delta x

Substituting the values of
\displaystyle y_(i) and
\displaystyle \Delta x into the formula, we can evaluate the sum and compute the estimated volume.


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User Catalin DICU
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8.3k points