- #1
D_Tr
- 45
- 4
This is not homework but is part of the solution process of an ODE and I cannot understand how the author made a derivation step. After a change of variable in the original ODE, the ODE in the new independent variable has a standard method of solution. But instead of using this method, the author takes a shortcut but the exact steps are skipped and I cannot reproduce the transition on my own.
How do we go from: [itex]y'' + 2y^{-3} = 0[/itex] to: [itex]y' = \sqrt{2(c_1 + 1/y^2)}[/itex] ?
The only hint given by the author is: "...but in this case we can multiply through by y' and integrate directly to obtain..."
N/A
I tried myltiplying through by y' and integrating both sides by parts but that gave me nothing I could use to go further.. I cannot even get back the first eq. by differentiating the second..
Homework Statement
How do we go from: [itex]y'' + 2y^{-3} = 0[/itex] to: [itex]y' = \sqrt{2(c_1 + 1/y^2)}[/itex] ?
The only hint given by the author is: "...but in this case we can multiply through by y' and integrate directly to obtain..."
Homework Equations
N/A
The Attempt at a Solution
I tried myltiplying through by y' and integrating both sides by parts but that gave me nothing I could use to go further.. I cannot even get back the first eq. by differentiating the second..