Trigonometric Integral excersice

alba_ei
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Homework Statement


Integral of \int \sin^{11/3}\alpha\, d\alpha


Homework Equations


\sin^2\alpha = 1 - cos^2\alpha


The Attempt at a Solution


\int (\sin^2\alpha)^{4/3}\sin\alpha \, d\alpha

\int (1-cos^2\alpha)^{4/3}\sin\alpha \, d\alpha

u = \cos\alphad
du = \sin\alpha\, d\alpha

\int (1-u^2)^{4/3} du
i don't know what else to do. any hints or tips?
 
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Interesting integral. Mathematica returns an answer involving the Gauss hypergeometric function _{2}F_{1}
 
the integral seems pretty hopeless to evaluate due to the cubic root... are there bounds to the integral? that could potentially simply things a whole lot.
 
tim_lou said:
the integral seems pretty hopeless to evaluate due to the cubic root... are there bounds to the integral? that could potentially simply things a whole lot.

It doesn't have upper or lower limits I am just looking for the antiderivate
 
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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