Integralen av $$$9 i n t \sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)}$$$ med avseende på $$$x$$$
Relaterad kalkylator: Kalkylator för bestämda och oegentliga integraler
Din inmatning
Bestäm $$$\int 9 i n t \sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)}\, dx$$$.
Lösning
Tillämpa konstantfaktorregeln $$$\int c f{\left(x \right)}\, dx = c \int f{\left(x \right)}\, dx$$$ med $$$c=9 i n t$$$ och $$$f{\left(x \right)} = \sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)}$$$:
$${\color{red}{\int{9 i n t \sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)} d x}}} = {\color{red}{\left(9 i n t \int{\sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)} d x}\right)}}$$
Skriv om integranden:
$$9 i n t {\color{red}{\int{\sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)} d x}}} = 9 i n t {\color{red}{\int{\frac{\cos{\left(x \right)}}{\sin{\left(x \right)}} d x}}}$$
Låt $$$u=\sin{\left(x \right)}$$$ vara.
Då $$$du=\left(\sin{\left(x \right)}\right)^{\prime }dx = \cos{\left(x \right)} dx$$$ (stegen kan ses »), och vi har att $$$\cos{\left(x \right)} dx = du$$$.
Alltså,
$$9 i n t {\color{red}{\int{\frac{\cos{\left(x \right)}}{\sin{\left(x \right)}} d x}}} = 9 i n t {\color{red}{\int{\frac{1}{u} d u}}}$$
Integralen av $$$\frac{1}{u}$$$ är $$$\int{\frac{1}{u} d u} = \ln{\left(\left|{u}\right| \right)}$$$:
$$9 i n t {\color{red}{\int{\frac{1}{u} d u}}} = 9 i n t {\color{red}{\ln{\left(\left|{u}\right| \right)}}}$$
Kom ihåg att $$$u=\sin{\left(x \right)}$$$:
$$9 i n t \ln{\left(\left|{{\color{red}{u}}}\right| \right)} = 9 i n t \ln{\left(\left|{{\color{red}{\sin{\left(x \right)}}}}\right| \right)}$$
Alltså,
$$\int{9 i n t \sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)} d x} = 9 i n t \ln{\left(\left|{\sin{\left(x \right)}}\right| \right)}$$
Lägg till integrationskonstanten:
$$\int{9 i n t \sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)} d x} = 9 i n t \ln{\left(\left|{\sin{\left(x \right)}}\right| \right)}+C$$
Svar
$$$\int 9 i n t \sin{\left(x \right)} \cot{\left(x \right)} \csc{\left(x \right)}\, dx = 9 i n t \ln\left(\left|{\sin{\left(x \right)}}\right|\right) + C$$$A