Solve this diff. equation please

dcardeno

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Oct 9, 2014
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Hello friends, I can't solve this equation and would appreciate any help here

dy/dx=(y/x)*sin(y/x), with y(1/2)=Pi/4 using substitution u=y/x
 
Hello friends, I can't solve this equation and would appreciate any help here

dy/dx=(y/x)*sin(y/x), with y(1/2)=Pi/4 using substitution u=y/x

u = y/x

dy/dx = x*du/dx + u

Then

x*du/dx + u = u * sin(u) with u(1/2) = π/2

Continue......
 
u = y/x

dy/dx = x*du/dx + u

Then

x*du/dx + u = u * sin(u) with u(1/2) = π/2

Continue......

Thank you for your answer. I had tried that before and then come to a diff. equation with the form:

du/(u*(sin(u)-1))=(1/x)*dx

I cant solve the integral in the u side. Even tried that with Mathematica and it couldnt either. Maybe I'm not approaching this exercise right. Can you help me further? Thanks
 
Thank you for your answer. I had tried that before and then come to a diff. equation with the form:

du/(u*(sin(u)-1))=(1/x)*dx

I cant solve the integral in the u side. Even tried that with Mathematica and it couldnt either. Maybe I'm not approaching this exercise right. Can you help me further? Thanks

Why didn't you say that inyour original post?!

The integral on the LHS does not have any known closed-form solution. You may want to try "infinite series" solutions.
 
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