MHB How can we evaluate this indefinite integral of a definite integral?

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The discussion focuses on evaluating the indefinite integral of the definite integral $\int_{0}^{1} \sqrt{1-2\sqrt{x-x^2}}dx$. The integral is transformed into $\int_{0}^{1} |\sqrt{x}-\sqrt{1-x}|dx$, which simplifies the evaluation process. The next steps involve breaking the integral into two parts: from 0 to 1/2 and from 1/2 to 1, allowing for easier computation. Participants clarify that the original expression is indeed a definite integral, emphasizing the need for precise terminology. The conversation highlights the importance of understanding the transformation and evaluation of integrals in calculus.
juantheron
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Evaluation of Indefinite Integral $\displaystyle \int_{0}^{1} \sqrt{1-2\sqrt{x-x^2}}dx$

$\bf{My\; Try::}$ We can write the given Integral as

$\displaystyle \int_{0}^{1}\sqrt{\left(\sqrt{x}\right)^2+\left(\sqrt{1-x}\right)^2-2\sqrt{x}\cdot \sqrt{1-x}}dx$

So Integral Convert into $\displaystyle \int_{0}^{1}\left|\sqrt{x}-\sqrt{1-x}\right|dx$

Now How can i solve after that , explanation Required.

Thanks
 
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jacks said:
Evaluation of Indefinite Integral $\displaystyle \int_{0}^{1} \sqrt{1-2\sqrt{x-x^2}}dx$

$\bf{My\; Try::}$ We can write the given Integral as

$\displaystyle \int_{0}^{1}\sqrt{\left(\sqrt{x}\right)^2+\left(\sqrt{1-x}\right)^2-2\sqrt{x}\cdot \sqrt{1-x}}dx$

So Integral Convert into $\displaystyle \int_{0}^{1}\left|\sqrt{x}-\sqrt{1-x}\right|dx$

Now How can i solve after that , explanation Required.

Thanks

... the successive step is easy...

$\displaystyle \int_{0}^{1} |\sqrt{x} - \sqrt{1 - x}|\ dx = \int_{0}^{\frac{1}{2}} (\sqrt{1 - x} - \sqrt{x})\ dx + \int_{\frac{1}{2}}^{1} (\sqrt{x} - \sqrt{1 - x})\ d x $

Kind regards

$\chi$ $\sigma$
 
This is actually a DEFINITE integral...
 
There are probably loads of proofs of this online, but I do not want to cheat. Here is my attempt: Convexity says that $$f(\lambda a + (1-\lambda)b) \leq \lambda f(a) + (1-\lambda) f(b)$$ $$f(b + \lambda(a-b)) \leq f(b) + \lambda (f(a) - f(b))$$ We know from the intermediate value theorem that there exists a ##c \in (b,a)## such that $$\frac{f(a) - f(b)}{a-b} = f'(c).$$ Hence $$f(b + \lambda(a-b)) \leq f(b) + \lambda (a - b) f'(c))$$ $$\frac{f(b + \lambda(a-b)) - f(b)}{\lambda(a-b)}...

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