Question

Evaluate the integral
** in pic file below**

Answer 1

@Michele_Laino

Answer 2

Please you have to integrate by parts

Answer 3

can u plz show me the steps again? :)

Answer 4

@ganeshie8 @Destinymasha @fred_fred_burger

Answer 5

hint:
\[\begin{gathered}
\int {x\cos x\;dx = x\sin x - \int {\sin x\,dx = } } \hfill \\
= x\sin x + \cos x \hfill \\
\end{gathered} \]

Answer 6

yes, for xcos(x) by parts is the only approach:)

Answer 7

ok can u plz tell me what happens next? :)

Answer 8

he posted it all before I even came here:P

Answer 9

but he left something out

Answer 10

ok :)

Answer 11

well, he did it on purpose, but in a case of a definite integral, you just do that

Answer 12

plug in your limits and evaluate the integral

Answer 13

\(\large\color{slate}{\displaystyle\int\limits_{0}^{\pi/2}x\cos x~dx=~\left( x\sin x+\cos x\right)~{{\huge |}_{ 0}^{\pi/2}}}\)

Answer 14

alright what do i get as an answer? :)

Answer 15

i have to go soon im at the library and im doing my assignment and i can ask my dad for assistance on how i found the answer

Answer 16

\(\large\color{slate}{\displaystyle\int\limits_{0}^{\pi/2}x\cos x~dx=~\left[ x\sin x+\cos x\color{white}{\LARGE|}\right]~{{\huge |}_{ 0}^{\pi/2}} \\=\left[ (\pi/2)\sin (\pi/2)+\cos (\pi/2)\color{white}{\LARGE|}\right]~-~\left[ (0)\sin (0)+\cos (0)\color{white}{\LARGE|}\right]}\)

this is all you are doing....