Funktion $$$\left(x^{2} + 1\right)^{2}$$$ integraali

Määritä $$$\int \left(x^{2} + 1\right)^{2}\, dx$$$.

Expand the expression:

$${\color{red}{\int{\left(x^{2} + 1\right)^{2} d x}}} = {\color{red}{\int{\left(x^{4} + 2 x^{2} + 1\right)d x}}}$$

Integroi termi kerrallaan:

$${\color{red}{\int{\left(x^{4} + 2 x^{2} + 1\right)d x}}} = {\color{red}{\left(\int{1 d x} + \int{2 x^{2} d x} + \int{x^{4} d x}\right)}}$$

Sovella vakiosääntöä $$$\int c\, dx = c x$$$ käyttäen $$$c=1$$$:

$$\int{2 x^{2} d x} + \int{x^{4} d x} + {\color{red}{\int{1 d x}}} = \int{2 x^{2} d x} + \int{x^{4} d x} + {\color{red}{x}}$$

Sovella potenssisääntöä $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ käyttäen $$$n=4$$$:

$$x + \int{2 x^{2} d x} + {\color{red}{\int{x^{4} d x}}}=x + \int{2 x^{2} d x} + {\color{red}{\frac{x^{1 + 4}}{1 + 4}}}=x + \int{2 x^{2} d x} + {\color{red}{\left(\frac{x^{5}}{5}\right)}}$$

Sovella vakiokertoimen sääntöä $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ käyttäen $$$c=2$$$ ja $$$f{\left(x \right)} = x^{2}$$$:

$$\frac{x^{5}}{5} + x + {\color{red}{\int{2 x^{2} d x}}} = \frac{x^{5}}{5} + x + {\color{red}{\left(2 \int{x^{2} d x}\right)}}$$

Sovella potenssisääntöä $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ käyttäen $$$n=2$$$:

$$\frac{x^{5}}{5} + x + 2 {\color{red}{\int{x^{2} d x}}}=\frac{x^{5}}{5} + x + 2 {\color{red}{\frac{x^{1 + 2}}{1 + 2}}}=\frac{x^{5}}{5} + x + 2 {\color{red}{\left(\frac{x^{3}}{3}\right)}}$$

Näin ollen,

$$\int{\left(x^{2} + 1\right)^{2} d x} = \frac{x^{5}}{5} + \frac{2 x^{3}}{3} + x$$

Lisää integrointivakio:

$$\int{\left(x^{2} + 1\right)^{2} d x} = \frac{x^{5}}{5} + \frac{2 x^{3}}{3} + x+C$$

$$$\int \left(x^{2} + 1\right)^{2}\, dx = \left(\frac{x^{5}}{5} + \frac{2 x^{3}}{3} + x\right) + C$$$A