Question

\[\int tanxdx\]
integration by parts

Answer 1

i integrate it twice; but i dont know why it failed

Answer 2

separate them into tanx and dx

Answer 3

i did\[(tanx)(x) - \int\limits xsec^{2}dx \]

Answer 4

integral sin x /cos x
put t= cos x

Answer 5

i know..but i want to do it by parts

Answer 6

- ln |cos x| + C

proof
int tan x dx = int sinx/cos x
set
u=cosx
then we find
du=-sinx dx
substitute du=-sin x, u=cos x

int sinx/cos x= - int of (-1) sin x dx / cosx
=- int of du/u

Solve the integral

= - ln |u| + C

substitute back u=cos x
= - ln |cos x| + C

Answer 7

ok @Omniscience

Answer 8

i know u-sub

i want to do it by parts

Answer 9

http://wiki.answers.com/Q/Integration_by_parts_of_x_tanx

Answer 10

i think it will help you!!!

Answer 11

that's \(xtanx\)

Answer 12

oh!!! sorry

Answer 13

maybe you could try converting tan x to sinx/cosx. then integrate sinxsecx by parts?

Answer 14

ok i will try it

Answer 15

wait. is the ans ln|secx|?

Answer 16

-ln(cosx)

Answer 17

looks the same lol

Answer 18

sec x is (cosx)^-1 bring the -1 to the front

Answer 19

yup thats the answer

Answer 20

ok thanks