Integraal van $$$\frac{t}{2 x - 5}$$$ met betrekking tot $$$x$$$

Bepaal $$$\int \frac{t}{2 x - 5}\, dx$$$.

Pas de constante-veelvoudregel $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ toe met $$$c=t$$$ en $$$f{\left(x \right)} = \frac{1}{2 x - 5}$$$:

$${\color{red}{\int{\frac{t}{2 x - 5} d x}}} = {\color{red}{t \int{\frac{1}{2 x - 5} d x}}}$$

Zij $$$u=2 x - 5$$$.

Dan $$$du=\left(2 x - 5\right)^{\prime }dx = 2 dx$$$ (de stappen zijn te zien »), en dan geldt dat $$$dx = \frac{du}{2}$$$.

De integraal kan worden herschreven als

$$t {\color{red}{\int{\frac{1}{2 x - 5} d x}}} = t {\color{red}{\int{\frac{1}{2 u} d u}}}$$

Pas de constante-veelvoudregel $$$\int c f{\left(u \right)}\, du = c \int f{\left(u \right)}\, du$$$ toe met $$$c=\frac{1}{2}$$$ en $$$f{\left(u \right)} = \frac{1}{u}$$$:

$$t {\color{red}{\int{\frac{1}{2 u} d u}}} = t {\color{red}{\left(\frac{\int{\frac{1}{u} d u}}{2}\right)}}$$

De integraal van $$$\frac{1}{u}$$$ is $$$\int{\frac{1}{u} d u} = \ln{\left(\left|{u}\right| \right)}$$$:

$$\frac{t {\color{red}{\int{\frac{1}{u} d u}}}}{2} = \frac{t {\color{red}{\ln{\left(\left|{u}\right| \right)}}}}{2}$$

We herinneren eraan dat $$$u=2 x - 5$$$:

$$\frac{t \ln{\left(\left|{{\color{red}{u}}}\right| \right)}}{2} = \frac{t \ln{\left(\left|{{\color{red}{\left(2 x - 5\right)}}}\right| \right)}}{2}$$

Dus,

$$\int{\frac{t}{2 x - 5} d x} = \frac{t \ln{\left(\left|{2 x - 5}\right| \right)}}{2}$$

Voeg de integratieconstante toe:

$$\int{\frac{t}{2 x - 5} d x} = \frac{t \ln{\left(\left|{2 x - 5}\right| \right)}}{2}+C$$

$$$\int \frac{t}{2 x - 5}\, dx = \frac{t \ln\left(\left|{2 x - 5}\right|\right)}{2} + C$$$A