Question

Integral of: tan(x)dx ? How do you do it?

Answer 1

convert tan(x) to sin(x)/cos(x), first

Answer 2

then we can use integral by u-subs
let u = cos(x)

Answer 3

Could you do it by parts?

Answer 4

i ever do it by part, but it doesnt work
just do it by u-subs

Answer 5

ok i try...

Answer 6

sipp.. get ur answer

Answer 7

dont stress me ;-)

Answer 8

which parts make be strses :P

Answer 9

actually. it is just a basic to learning integration by u-subs
may be this site useful :)
http://math2.org/math/integrals/more/tan.htm

Answer 10

got it: -ln(cos(x))

Answer 11

yup :)

Answer 12

My teacher actually wrote -ln(lcos(x)l) do you know why?

Answer 13

dont forget + c

Answer 14

right thanx

Answer 15

why the absolute value?

Answer 16

you can't take ln of negative value , that's why absoloute value

Answer 17

why can't you?