Mathematics
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OpenStudy (christos):
integral of 1/(u^3) ?
12 years ago
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OpenStudy (christos):
@zzr0ck3r u there?
12 years ago
OpenStudy (jhannybean):
\[\large \int\limits \frac{ 1 }{ u^3 }du= \int\limits u^{-3}du\] you know how to integrate that right.
12 years ago
OpenStudy (christos):
to tell you the truth I already knew how to do it, I just think this exersise is wrong so I need to verify, look at the bottom
http://screencast.com/t/XEJ9Dmj1S
12 years ago
OpenStudy (zzr0ck3r):
looks good
12 years ago
OpenStudy (christos):
my result: (1/2)*((-1/18) + (1/72))
12 years ago
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OpenStudy (zzr0ck3r):
what is the problem?
12 years ago
OpenStudy (christos):
Just making sure I didnt miss anything lol
12 years ago
OpenStudy (anonymous):
where did the \(\frac{1}{18}\) come from ?
12 years ago
OpenStudy (zzr0ck3r):
the solution looks fine
12 years ago
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OpenStudy (christos):
3^2 = 9*2 = 18
12 years ago
OpenStudy (zzr0ck3r):
show us what you did, did u change your bounds when you substituted?
12 years ago
OpenStudy (zzr0ck3r):
3^2 = 3*3 = 9
12 years ago
OpenStudy (anonymous):
three squared is not equal to nine squared
12 years ago
OpenStudy (christos):
9*2(denominator) = 18
12 years ago
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OpenStudy (zzr0ck3r):
18 = 2*3^2
12 years ago
OpenStudy (christos):
Right
12 years ago
OpenStudy (zzr0ck3r):
I m confused:)
12 years ago
OpenStudy (christos):
;p
12 years ago
OpenStudy (anonymous):
\[F(u)=-\frac{1}{4u^2}\]
\[F(3)-F(6)=-\frac{1}{4}\left(\frac{1}{9}-\frac{1}{36}\right)\]
12 years ago
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OpenStudy (christos):
where did the 1/4 come from
12 years ago
OpenStudy (christos):
there might be a probability that my solution and the other one are equal idk
12 years ago
OpenStudy (christos):
:D
12 years ago
OpenStudy (anonymous):
the u - sub gave a factor of \(\frac{1}{2}\) and the anti derivative gave another \(-\frac{1}{2}\)
12 years ago
OpenStudy (christos):
aah!
12 years ago
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OpenStudy (christos):
hold on
12 years ago
OpenStudy (christos):
That was the trick, thank you
12 years ago
OpenStudy (anonymous):
yw
12 years ago