Mathematica error when solving a DE -- "exceeded RecursionLimit"

[Abhisheko07]

Homework Statement:: I don't know where the mistake is happening. I need to solve the give differential equation in mathematica and have to plot it but i am facing problem in doing so.
Can anyone help me in this?
Relevant Equations:: I have attached the picture of equation as well as my mathematica code.

 

[Delta2]

not sure, maybe try sol=DSolve[eqn,y[x],x], that is put y[x] there instead of just y.
Also try putting the equation explicitly into the DSolve command, for example like
sol=Dsolve[y''[x]==-y[x],y[x],x]

 

[Dale]

What is x. It looks like x is defined somewhere above. Try clearing x first and then re run your code