- #1
Dell
- 590
- 0
the given integral is:
[tex]\int[/tex][tex]\frac{dx}{ln(x)}[/tex] (from 0 to 1)
now i have a problem at both ends of the integral, because i have ln(0) is undefinde and ln(1) is 0 and 1/0 is undefined, so i can integrate from 0 to 0.5 and 0.5 to 1, but i tried to integrate this and just couldnt, i tried substitution
t=ln(x)
x=et
dt=dx/x
and then tried integration in parts but this just didnt work,
so then i thought maybe i need to find a similar function which i know more about or can easily find more about, but again i have problems at both limits, so i think i need 2 separate functions, since i know that 1/ln(x) is negative in the limits 0-1, i will take the abs value of 1/ln(x) and look for positive functions...
i am looking for an integral that is either
*bigger than my original integral and converges
*smaller than my original integral and diverges
what i found was
[tex]\int[/tex]dx/[tex]\sqrt{x}[/tex] (from 0 to 0.4) which converges and is bigger than [tex]\int[/tex]dx/|ln(x)| (from 0 to 0.4 )
and my second integral is [tex]\int[/tex]1/x (from 0.6 to 1) which diverges and is smaller than [tex]\int[/tex]dx/|ln(x)| (from 0.6 to 1 )
therefore i know that the integral [tex]\int[/tex][tex]\frac{dx}{ln(x)}[/tex] (from 0 to 1) diverges near 1, and converges near 0, so all in all it diverges.
is this okay? is it alright that i didnt take into account the area between 0.4 and 0.6 since the function is constant there anyway??
can you see any better way to solve this??
[tex]\int[/tex][tex]\frac{dx}{ln(x)}[/tex] (from 0 to 1)
now i have a problem at both ends of the integral, because i have ln(0) is undefinde and ln(1) is 0 and 1/0 is undefined, so i can integrate from 0 to 0.5 and 0.5 to 1, but i tried to integrate this and just couldnt, i tried substitution
t=ln(x)
x=et
dt=dx/x
and then tried integration in parts but this just didnt work,
so then i thought maybe i need to find a similar function which i know more about or can easily find more about, but again i have problems at both limits, so i think i need 2 separate functions, since i know that 1/ln(x) is negative in the limits 0-1, i will take the abs value of 1/ln(x) and look for positive functions...
i am looking for an integral that is either
*bigger than my original integral and converges
*smaller than my original integral and diverges
what i found was
[tex]\int[/tex]dx/[tex]\sqrt{x}[/tex] (from 0 to 0.4) which converges and is bigger than [tex]\int[/tex]dx/|ln(x)| (from 0 to 0.4 )
and my second integral is [tex]\int[/tex]1/x (from 0.6 to 1) which diverges and is smaller than [tex]\int[/tex]dx/|ln(x)| (from 0.6 to 1 )
therefore i know that the integral [tex]\int[/tex][tex]\frac{dx}{ln(x)}[/tex] (from 0 to 1) diverges near 1, and converges near 0, so all in all it diverges.
is this okay? is it alright that i didnt take into account the area between 0.4 and 0.6 since the function is constant there anyway??
can you see any better way to solve this??