Integralen av $$$4 \sqrt{x} - \frac{3}{x^{2}}$$$

Bestäm $$$\int \left(4 \sqrt{x} - \frac{3}{x^{2}}\right)\, dx$$$.

Integrera termvis:

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

Tillämpa konstantfaktorregeln $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ med $$$c=3$$$ och $$$f{\left(x \right)} = \frac{1}{x^{2}}$$$:

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

Tillämpa potensregeln $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ med $$$n=-2$$$:

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

Tillämpa konstantfaktorregeln $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ med $$$c=4$$$ och $$$f{\left(x \right)} = \sqrt{x}$$$:

$${\color{red}{\int{4 \sqrt{x} d x}}} + \frac{3}{x} = {\color{red}{\left(4 \int{\sqrt{x} d x}\right)}} + \frac{3}{x}$$

Tillämpa potensregeln $$$\int x^{n}\, dx = \frac{x^{n + 1}}{n + 1}$$$ $$$\left(n \neq -1 \right)$$$ med $$$n=\frac{1}{2}$$$:

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

Alltså,

$$\int{\left(4 \sqrt{x} - \frac{3}{x^{2}}\right)d x} = \frac{8 x^{\frac{3}{2}}}{3} + \frac{3}{x}$$

Förenkla:

$$\int{\left(4 \sqrt{x} - \frac{3}{x^{2}}\right)d x} = \frac{8 x^{\frac{5}{2}} + 9}{3 x}$$

Lägg till integrationskonstanten:

$$\int{\left(4 \sqrt{x} - \frac{3}{x^{2}}\right)d x} = \frac{8 x^{\frac{5}{2}} + 9}{3 x}+C$$

$$$\int \left(4 \sqrt{x} - \frac{3}{x^{2}}\right)\, dx = \frac{8 x^{\frac{5}{2}} + 9}{3 x} + C$$$A