Integrating xsecx

How do I integrate xsecx? Tried doing it by parts, but no luck. Need it to solve a question of Differential Equations.

Thanks in advance.

Reply 1

insparato

Show us you're working. I havent entirely worked through it but u = x dv = secx and doing by parts twice might work.

Reply 2

Fire Wolf

My scanner isn't working, but when I tried it by parts, couldn't go further because the integration of log (secx+tanx) came up.

I didn't understand your substitution of u = x dv = secx.

Reply 3

nota bene

Fire Wolf

I didn't understand your substitution of u = x dv = secx.

It wasn't a substitution, it was by parts

\int udv=uv-\int vdu

(where u and v are functions of x).

That said, mathematica gave me an answer that cannot be expressed in elementary functions, so I suspect something is wrong with the question...
(if a DE, check your working up to coming to having to integrate xsecx...)

Reply 4

insparato

No it doesnt work, just actually tried it now.

Might want to check your DE.

Reply 5

OCC++

ar after some research...

this question is doable by parts
the hard part is to integrate sec x.
the reason why its very hard to integrate it is because its so hard that it is actually provided in (at least for mine) the official formula list.
just for refernce to all,
integration of sec x is ln |sec x + tan x |