integral sin(1/x) dx ?

Question

anonymous · Answer

xsin(1/x) - Ci(1/x) + C

anonymous · Answer

what on earth?

anonymous · Answer

you can't integrate this thing.  where did the question come from?

anonymous · Answer

anonymous · Answer

$$\int\limits 8x^2 \sin (1/10 x) dx$$

anonymous · Answer

thats where the question came from

anonymous · Answer

for the love of pete, wolfram doesn't give an answer! it gives the integral in terms of another integral.

anonymous · Answer

$$8\int x^2\sin(\frac{1}{10}x)dx$$ like that?

anonymous · Answer

yes

anonymous · Answer

so it is really 
$$\sin(\frac{x}{10})$$ not 
$$\sin(\frac{1}{10x})$$

anonymous · Answer

hahahahahah sorry

anonymous · Answer

integrate by parts twice.  pain in the butt, but if you want to use wolfram and follow the steps at least you will get a real answer this time

anonymous · Answer

ok thanks

anonymous · Answer

here you can look at this. but the basic idea is to integrate sin and differen tiate x^2. then you will have to do it once more http://www.wolframalpha.com/input/?i=integral+x^2sin%28x%2F%2810%29%29