Příklad 4.48
[!example] Vypočtěte $\(\Large \int_{0}^{1} \frac{2-3\arcsin(x)}{\sqrt{1-x^2}}\;dx\)$
\[
\begin{aligned}
&\int_{0}^{1} \frac{2-3\arcsin(x)}{\sqrt{1-x^2}}\;dx \\
&= \int_{0}^{1} \frac{2}{\sqrt{1-x^2}}\;dx - \int_{0}^{1} \frac{3\arcsin(x)}{\sqrt{1-x^2}}\;dx \\
&= 2\int_{0}^{1} \frac{1}{\sqrt{1-x^2}}\;dx - 3\int_{0}^{1} \frac{\arcsin(x)}{\sqrt{1-x^2}}\;dx
\end{aligned}
\]
[!tip]+ Substituce
\[\large\begin{aligned} u &= \arcsin(x) \\ du &= \frac{1}{\sqrt{1-x^2}}dx \\ \end{aligned}\][!info] $\(\arcsin(0) = 0\)$ $\(\arcsin(1) = \frac{\pi}{2}\)$
\[
\begin{aligned}
&= 2\int_{0}^{1} \frac{1}{\sqrt{1-x^2}}\;dx - 3\int_{0}^{1} \frac{\arcsin(x)}{\sqrt{1-x^2}}\;dx \\
&= 2\int_{0}^{\frac{\pi}{2}}\;du - 3\int_{0}^{\frac{\pi}{2}} u\;du \\
&= 2\cdot\left[u\right]_{0}^{\frac{\pi}{2}} - 3\cdot\left[\frac{u^2}{2}\right]_{0}^{\frac{\pi}{2}} \\
&= \cancel{2}\frac{\pi}{\cancel{2}} - 3\cdot\left[\frac{\left(\frac{\pi}{2}\right)^2}{2} - \frac{0}{2}\right] \\
&= \pi -3 \cdot \left[\frac{\pi^2}{4}\cdot\frac{1}{2}\right] \\
&= \boxed{\pi - \frac{3\pi^2}{8}} \\
\end{aligned}
\]