Solving a Complicated Integral: Exploring Substitution Method

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Integrate \int \frac{\left(5x - x^{2}\right)^{2}}{2}

I have been going round in circles using the substitution of u = \left(5x - x^{2}\right)

But it gets too complicated, where am I going wrong? I would really appreciate it if someone could please explain in stages what exactly I have to do.
Many thanks
 
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\frac 1 2\int(5x-x^2)^2dx

Don't forget your dx.

Expand ... (x-y)^2=x^2-2xy+y^2
 
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Is the solution anywhere close to this?

\frac{\left(25x ^{3}\right)}{6} - \frac{\left(10x ^{4}\right)}{4} + \frac{\left(x ^{5}\right)}{5}

Thanks,
 
Oh yeah of course it is, thanks to you all. Panic over!
 
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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