Math Is Fun Forum
  Discussion about math, puzzles, games and fun.   Useful symbols: √ ∞ ≠ ≤ ≥ ≈ ⇒ ∈ Δ θ ∴ ∑ ∫ π -

Login

Username

Password

Not registered yet?

Post a reply

Go back

Write your message and submit
:) :| :( :D :o ;) :/ :P :lol: :mad: :rolleyes: :cool: | :dizzy :eek :kiss :roflol :rolleyes :shame :down :up :touched :sleep :wave :swear :tongue :what :faint :dunno
Options

Go back

Topic review (newest first)

anonimnystefy
2013-01-26 13:30:01

You're welcome! smile

White_Owl
2013-01-26 04:31:27


Yes, it does look promising.
Thank you very much.

anonimnystefy
2013-01-25 09:55:19

Hi White_Owl

You have multiplied by 3 instead of dividing by 3 when making the substitution...

White_Owl
2013-01-25 09:21:44

Ok... Then:


And after substituting back u for x I have:


But now if I differentiate it back:

Where did 9 come from?

anonimnystefy
2013-01-25 07:42:10

Hi White_Owl

Continuing on the first thing you tried:



Can you continue from here?

White_Owl
2013-01-25 07:23:56

In my homework for this week I have a question:



If I do a substitution u=3x+25, then I have

Which does not help much.



If I try to find such u that du will eliminate x from numerator, then: du=1/x dx and u have to be ln(x)

Which is also not very helpful...



Finally I run the original integral through Maxima, and it gave me:

Which is very scary and I have no idea how it come to this formula.


So which "u" should I use? How to find such "u"? Or maybe there is another approach I should use? I am completely stuck.

Board footer

Powered by FluxBB