revolution of an arc

logistic_guy

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Find the surface area generated when the given arc is revolved about the given axis.

y=x3,  0x1\displaystyle y = x^3, \ \ 0 \leq x \leq 1, about the x\displaystyle x-axis.
 
Find the surface area generated when the given arc is revolved about the given axis.

y=x3,  0x1\displaystyle y = x^3, \ \ 0 \leq x \leq 1, about the x\displaystyle x-axis.
show us your effort/s to solve this problem.
 
Surface Area =012πf(x)1+[f(x)]2 dx\displaystyle = \int_{0}^{1}2\pi f(x)\sqrt{1 + [f'(x)]^2} \ dx

f(x)=y=x3\displaystyle f(x) = y = x^3
f(x)=3x2\displaystyle f'(x) = 3x^2

Surface Area =012πx31+9x4 dx=π18110u du=π1823u3/2110=π1823(10101)3.6\displaystyle = \int_{0}^{1}2\pi x^3\sqrt{1 + 9x^4} \ dx = \frac{\pi}{18}\int_{1}^{10}\sqrt{u} \ du = \frac{\pi}{18}\frac{2}{3}u^{3/2}\bigg|_{1}^{10} = \frac{\pi}{18}\frac{2}{3}\left(10\sqrt{10} - 1\right) \approx 3.6
 
First makes post with no work shown and then posts the solution. This is in violation of the posting guidelines.
Reported this OP to the admin---again
 
Surface Area =012πf(x)1+[f(x)]2 dx\displaystyle = \int_{0}^{1}2\pi f(x)\sqrt{1 + [f'(x)]^2} \ dx

f(x)=y=x3\displaystyle f(x) = y = x^3
f(x)=3x2\displaystyle f'(x) = 3x^2

Surface Area =012πx31+9x4 dx=π18110u du=π1823u3/2110=π1823(10101)3.6\displaystyle = \int_{0}^{1}2\pi x^3\sqrt{1 + 9x^4} \ dx = \frac{\pi}{18}\int_{1}^{10}\sqrt{u} \ du = \frac{\pi}{18}\frac{2}{3}u^{3/2}\bigg|_{1}^{10} = \frac{\pi}{18}\frac{2}{3}\left(10\sqrt{10} - 1\right) \approx 3.6
This am old problem
 
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