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brainslush
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Homework Statement
The radius r of a wire of length L increases according to r = a * exp(bx^2), x is the distance from one end to the other end of the wire. What is the resistance of the wire?
Homework Equations
[itex]R =\frac{L * \rho}{A}[/itex]
The Attempt at a Solution
[itex]dR =\frac{dx * \rho}{A}[/itex]
[itex]A(r) = \pi * r^2[/itex]
[itex]r(x) = a* e^{bx^2}[/itex]
[itex]A(x) =\pi a^2 * e^{2bx^2}[/itex]
[itex]R =\int^{L}_{0}\frac{\rho}{\pi a^2 * e^{2bx^2}}*dx[/itex]
Two questions
First of all. Is this approach correct? And second, how does one integrate an errorfunction? (Of course one can use WolframAlpha but how does one get this solution?)
Thanks
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