MHB First Order Nonlinear Differential Equation

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The discussion revolves around solving a first-order nonlinear differential equation given by (dy/dx)^2 = (ay^4/2) - (a+1)y^2 + 1, with initial conditions y(0)=0 and y'(0)=1, where a is in the range [0,1]. The original poster expresses frustration over the complexity of the solution, suggesting it should be simpler. Respondents note that a direct approach leads to an elliptic integral, which complicates the solution further. Despite the challenges, there is encouragement to explore alternative methods. The conversation highlights the inherent difficulties in solving nonlinear differential equations.
frank1234
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Hi, I need help solving this ode, when I try to solve it I end up with a big crazy answer and I believe it should be simpler.

(dy/dx)^2=((ay^4)/2)-(a+1)y^2+1

y(0)=0, y'(0)=1 and a is within [0,1]
 
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frank1234 said:
Hi, I need help solving this ode, when I try to solve it I end up with a big crazy answer and I believe it should be simpler.

(dy/dx)^2=((ay^4)/2)-(a+1)y^2+1

y(0)=0, y'(0)=1 and a is within [0,1]

I'm not surprised because that is the natural consequence of ...

http://mathhelpboards.com/differential-equations-17/need-help-solving-2nd-order-nonlinear-differential-equation-12222.html#post58240

Unfortunately the 'direct attack' to the ODE...

$\displaystyle y^{\ '} = \sqrt{a\ y^{4} - (1 + a) y^{2} + 1}\ (1)$

... leads to an elliptic integral, a rather indigestible dish:( ... but never say never again!...

By the way, welcome to MHB! :)...

Kind regards

$\chi$ $\sigma$
 

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