I'm having issues solving a 1st order ODE.(adsbygoogle = window.adsbygoogle || []).push({});

Here what happens:

NDSolve[{y'[x]/y[x] == k *Pi* r^2* Sqrt[1 + y'[x]^2], y[0] == 136/10}, y[x], {x, 0, 30}]

NDSolve::ndnum: Encountered non-numerical value for a derivative at x == 0.

Changing the x range is no help... I get the same message for any initial point...

k and r are given parameters.

Any idea what's wrong in my code?

Thanks

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# ODE solution with Mathematica 8

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