# Coupled differential equation using NDSolve

I am using mathematica to solve a coupled differential equation using NDSOlve and stuck with it. Could you please help me out to figure out the solution. My problem is

$$A[\omega]:= A''[r]+\frac{f'[r]}{f[r]}A'[r]+\frac{\omega^2}{f[r]^2}-\frac{\mu^2}{f[r]}A[r]+\frac{\mu}{I \omega}S[r]=0$$, $$S''[r] + \frac{f'[r]}{f[r]}S'[r] + \frac{\omega^2}{f[r]^2}S[r]- \frac{1}{U[r]^2} h[r]=0$$ and $$S[r]=\frac{I \omega}{f[r]}(\mu A[r]+h'[r]-h[r])$$

• "stuck with it" - can you show the code you used? – J. M. will be back soon Jul 19 '16 at 6:03
• Welcome! I suggest the following: 1) As you receive help, try to give it too, by answering questions in your area of expertise. 2) Take the tour and check the faqs! 3) When you see good questions and answers, vote them up by clicking the gray triangles, because the credibility of the system is based on the reputation gained by users sharing their knowledge. Remember to accept the answer, if any, that solves your problem, by clicking the checkmark sign! – user9660 Jul 19 '16 at 6:13
• People here generally like users to post code as Mathematica code instead of images or TeX, so they can copy-paste it. It makes it convenient for them and more likely you will get someone to help you. – user9660 Jul 19 '16 at 6:13
• – user9660 Jul 19 '16 at 6:13
• OP also has network issues... – István Zachar Jul 19 '16 at 7:30

Too long for comment: There's a difference between equation == and setting a variable=. In the NDSolve[] you appear to be "setting" h[0]=1 You need to change this to an equation ==, then quit the kernel (so that h[0] is "unset", and try running the code again.
I would also like to advise you that it is considered bad form to use single capital letter variables like A.
• Good eye, spotting = ... – Anton Antonov Jul 20 '16 at 14:07