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kevtimc
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Homework Statement
y = sin [tex]\pi[/tex]x Using arc length and surface revoultion on x-axis 0 <= x <= 1
The Attempt at a Solution
d/dx sin [tex]\pi[/tex]x = [tex]\pi[/tex] cos [tex]\pi[/tex]x
([tex]\pi[/tex] cos[tex]\pi[/tex]x)^2 = [tex]\pi[/tex]^2 cos^2[tex]\pi[/tex]x
[tex]\int sin pi * x * 2 * pi * \sqrt{1 + pi^2 * cos^2 (pi*x)} [/tex]
u = pi cos (pi * x)
du = -pi^2 * sin (pi * x) dx
-1/2pi[tex] \int \sqrt{1 + u^2}[/tex]
u = tan [tex]\alpha[/tex]
du = sec^2 [tex]\alpha[/tex]
We get the integral of sec^3,
This doesn't seem to be right, and if it is, the limits of integration don't work out . . .
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