Integralen av $$$\cos{\left(x \right)} + 1$$$

Bestäm $$$\int \left(\cos{\left(x \right)} + 1\right)\, dx$$$.

Integrera termvis:

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

Tillämpa konstantregeln $$$\int c\, dx = c x$$$ med $$$c=1$$$:

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

Integralen av cosinus är $$$\int{\cos{\left(x \right)} d x} = \sin{\left(x \right)}$$$:

$$x + {\color{red}{\int{\cos{\left(x \right)} d x}}} = x + {\color{red}{\sin{\left(x \right)}}}$$

Alltså,

$$\int{\left(\cos{\left(x \right)} + 1\right)d x} = x + \sin{\left(x \right)}$$

Lägg till integrationskonstanten:

$$\int{\left(\cos{\left(x \right)} + 1\right)d x} = x + \sin{\left(x \right)}+C$$

$$$\int \left(\cos{\left(x \right)} + 1\right)\, dx = \left(x + \sin{\left(x \right)}\right) + C$$$A