Integraal van $$$5 \sqrt[3]{2 x + 4}$$$

Bepaal $$$\int 5 \sqrt[3]{2 x + 4}\, dx$$$.

Vereenvoudig de integraand:

$${\color{red}{\int{5 \sqrt[3]{2 x + 4} d x}}} = {\color{red}{\int{5 \sqrt[3]{2} \sqrt[3]{x + 2} d x}}}$$

Pas de constante-veelvoudregel $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ toe met $$$c=5 \sqrt[3]{2}$$$ en $$$f{\left(x \right)} = \sqrt[3]{x + 2}$$$:

$${\color{red}{\int{5 \sqrt[3]{2} \sqrt[3]{x + 2} d x}}} = {\color{red}{\left(5 \sqrt[3]{2} \int{\sqrt[3]{x + 2} d x}\right)}}$$

Zij $$$u=x + 2$$$.

Dan $$$du=\left(x + 2\right)^{\prime }dx = 1 dx$$$ (de stappen zijn te zien »), en dan geldt dat $$$dx = du$$$.

De integraal kan worden herschreven als

$$5 \sqrt[3]{2} {\color{red}{\int{\sqrt[3]{x + 2} d x}}} = 5 \sqrt[3]{2} {\color{red}{\int{\sqrt[3]{u} d u}}}$$

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

$$5 \sqrt[3]{2} {\color{red}{\int{\sqrt[3]{u} d u}}}=5 \sqrt[3]{2} {\color{red}{\int{u^{\frac{1}{3}} d u}}}=5 \sqrt[3]{2} {\color{red}{\frac{u^{\frac{1}{3} + 1}}{\frac{1}{3} + 1}}}=5 \sqrt[3]{2} {\color{red}{\left(\frac{3 u^{\frac{4}{3}}}{4}\right)}}$$

We herinneren eraan dat $$$u=x + 2$$$:

$$\frac{15 \sqrt[3]{2} {\color{red}{u}}^{\frac{4}{3}}}{4} = \frac{15 \sqrt[3]{2} {\color{red}{\left(x + 2\right)}}^{\frac{4}{3}}}{4}$$

Dus,

$$\int{5 \sqrt[3]{2 x + 4} d x} = \frac{15 \sqrt[3]{2} \left(x + 2\right)^{\frac{4}{3}}}{4}$$

Voeg de integratieconstante toe:

$$\int{5 \sqrt[3]{2 x + 4} d x} = \frac{15 \sqrt[3]{2} \left(x + 2\right)^{\frac{4}{3}}}{4}+C$$

$$$\int 5 \sqrt[3]{2 x + 4}\, dx = \frac{15 \sqrt[3]{2} \left(x + 2\right)^{\frac{4}{3}}}{4} + C$$$A