Integralen av $$$- z_{2} \left(3 z - 3\right) + 4$$$ med avseende på $$$z$$$

Bestäm $$$\int \left(- z_{2} \left(3 z - 3\right) + 4\right)\, dz$$$.

Integrera termvis:

$${\color{red}{\int{\left(- z_{2} \left(3 z - 3\right) + 4\right)d z}}} = {\color{red}{\left(\int{4 d z} - \int{z_{2} \left(3 z - 3\right) d z}\right)}}$$

Tillämpa konstantregeln $$$\int c\, dz = c z$$$ med $$$c=4$$$:

$$- \int{z_{2} \left(3 z - 3\right) d z} + {\color{red}{\int{4 d z}}} = - \int{z_{2} \left(3 z - 3\right) d z} + {\color{red}{\left(4 z\right)}}$$

Förenkla integranden:

$$4 z - {\color{red}{\int{z_{2} \left(3 z - 3\right) d z}}} = 4 z - {\color{red}{\int{3 z_{2} \left(z - 1\right) d z}}}$$

Tillämpa konstantfaktorregeln $$$\int c f{\left(z \right)}\, dz = c \int f{\left(z \right)}\, dz$$$ med $$$c=3 z_{2}$$$ och $$$f{\left(z \right)} = z - 1$$$:

$$4 z - {\color{red}{\int{3 z_{2} \left(z - 1\right) d z}}} = 4 z - {\color{red}{\left(3 z_{2} \int{\left(z - 1\right)d z}\right)}}$$

Integrera termvis:

$$4 z - 3 z_{2} {\color{red}{\int{\left(z - 1\right)d z}}} = 4 z - 3 z_{2} {\color{red}{\left(- \int{1 d z} + \int{z d z}\right)}}$$

Tillämpa konstantregeln $$$\int c\, dz = c z$$$ med $$$c=1$$$:

$$4 z - 3 z_{2} \left(\int{z d z} - {\color{red}{\int{1 d z}}}\right) = 4 z - 3 z_{2} \left(\int{z d z} - {\color{red}{z}}\right)$$

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

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

Alltså,

$$\int{\left(- z_{2} \left(3 z - 3\right) + 4\right)d z} = 4 z - 3 z_{2} \left(\frac{z^{2}}{2} - z\right)$$

Förenkla:

$$\int{\left(- z_{2} \left(3 z - 3\right) + 4\right)d z} = \frac{z \left(- 3 z_{2} \left(z - 2\right) + 8\right)}{2}$$

Lägg till integrationskonstanten:

$$\int{\left(- z_{2} \left(3 z - 3\right) + 4\right)d z} = \frac{z \left(- 3 z_{2} \left(z - 2\right) + 8\right)}{2}+C$$

$$$\int \left(- z_{2} \left(3 z - 3\right) + 4\right)\, dz = \frac{z \left(- 3 z_{2} \left(z - 2\right) + 8\right)}{2} + C$$$A