please help!! quick question an intergral (1 Viewer)

[Dm31]

hi

the question is:

(intergral sign) dx/(x(logx)^3)

^3 means power of 3 right? if not, that's what im trying to use it as

i got to the last stage, using logx as u, which was

(intergral sign) 1/((u)^3) = u^(-3)

= [-1/2(u)^(-2)]

= -1/2(logx)^(-2)

= -1/(2(logx^2))

this is where i got stuck.

the answer in the bak of the book is e^(sin(^-1)x)??????????

i'm completely lost, any help would be greatly appreicated!!!

 

[dawso]

i havent tried the question but i think u will find that ur rite...and so is the book, with integrals, sometimes certain answers can come out as log, some as inverse sine... i cant remember y or wat but remember sometin like, that, lol, um.....slide rule or someone smart...u answer the lady

 

[Slidey]

hi

the question is:

(intergral sign) dx/(x(logx)^3)

^3 means power of 3 right? if not, that's what im trying to use it as

i got to the last stage, using logx as u, which was

(intergral sign) 1/((u)^3) = u^(-3)

= [-1/2(u)^(-2)]

= -1/2(logx)^(-2)

= -1/(2(logx^2))

this is where i got stuck.

the answer in the bak of the book is e^(sin(^-1)x)??????????

i'm completely lost, any help would be greatly appreicated!!!

I have not covered 4unit integration yet, however my calculator verifies that you are correct.

It is possible the book is also correct, as dawso said... however, I doubt this.

 

[withoutaface]

hi

the question is:

(intergral sign) dx/(x(logx)^3)

^3 means power of 3 right? if not, that's what im trying to use it as

i got to the last stage, using logx as u, which was

(intergral sign) 1/((u)^3) = u^(-3)

= [-1/2(u)^(-2)]

= -1/2(logx)^(-2)

= -1/(2(logx^2))

this is where i got stuck.

the answer in the bak of the book is e^(sin(^-1)x)??????????

i'm completely lost, any help would be greatly appreicated!!!

I'll do my own working and you can check it against your own, right?

/
| dx/x(lnx)³
/
let u=lnx
du=dx/x

/
| du/u³
/

-1/2u² + C
-1/2(lnx)²+C
I think your answer is correct, and personally can't see how they got the other one, but if in doubt, sub some values in and see if they work.

 

[KFunk]

Your answer seems to be correct, make sure that you're looking at the right answer and that there's isn't a nearby question which looks like:


∫e^{sin^-1x}/√(1-x²) dx


EDIT: Just testing the symbols out, don't mind me. ∑ tan²θ ∞ φ τ ψ

 

[Dm31]

Ok thanx all =D