Integraal van $$$\frac{x^{3}}{\sqrt{1 - t^{2}}}$$$ met betrekking tot $$$x$$$

Bepaal $$$\int \frac{x^{3}}{\sqrt{1 - t^{2}}}\, dx$$$.

Pas de constante-veelvoudregel $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ toe met $$$c=\frac{1}{\sqrt{1 - t^{2}}}$$$ en $$$f{\left(x \right)} = x^{3}$$$:

$${\color{red}{\int{\frac{x^{3}}{\sqrt{1 - t^{2}}} d x}}} = {\color{red}{\frac{\int{x^{3} d x}}{\sqrt{1 - t^{2}}}}}$$

Pas de machtsregel $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ toe met $$$n=3$$$:

$$\frac{{\color{red}{\int{x^{3} d x}}}}{\sqrt{1 - t^{2}}}=\frac{{\color{red}{\frac{x^{1 + 3}}{1 + 3}}}}{\sqrt{1 - t^{2}}}=\frac{{\color{red}{\left(\frac{x^{4}}{4}\right)}}}{\sqrt{1 - t^{2}}}$$

Dus,

$$\int{\frac{x^{3}}{\sqrt{1 - t^{2}}} d x} = \frac{x^{4}}{4 \sqrt{1 - t^{2}}}$$

Voeg de integratieconstante toe:

$$\int{\frac{x^{3}}{\sqrt{1 - t^{2}}} d x} = \frac{x^{4}}{4 \sqrt{1 - t^{2}}}+C$$

$$$\int \frac{x^{3}}{\sqrt{1 - t^{2}}}\, dx = \frac{x^{4}}{4 \sqrt{1 - t^{2}}} + C$$$A