Solving ODE's with a and b parameters: Methods and Tips

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Damascus Road
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Hey all,

I have these 2 ODE's that I have to solve:

a.) y&#039; = ay - by^{3} ; a,b &gt; 0<br />
b.) y&#039; = (a cos(x) + b)y - y^{3}I'm not even exactly sure what method to use for these...

I tried splitting up the variables in a.) but it got kinda messy:

\int \frac{dy}{y(a-by^{2})} = \int dx

Is there a better way to approach it?
A method suggestion for b.) would be great!
 
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Hi Damascus Road! :smile:

For a.) use partial fractions on 1/y(a-by2) :wink:

For b.) … I've no idea :redface:
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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