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Mathematics 16 Online
OpenStudy (ashley1nonly):

integration by parts

OpenStudy (ashley1nonly):

\[7x^{2}\ln(3x)-(7/2)x ^{2}\]

OpenStudy (ashley1nonly):

343-ln(2)-(6160/36)

OpenStudy (ashley1nonly):

no minus between 343 and ln(2)

OpenStudy (ashley1nonly):

\[\int\limits_{1/3}^{7}14xln(3)dx\]

OpenStudy (turingtest):

\[\int\limits_{1/3}^{7}14x\ln(3x)dx\]?

OpenStudy (ashley1nonly):

yes

OpenStudy (turingtest):

are you just asking us to check your work? if so the indefinite is right, let me check your sub

OpenStudy (ashley1nonly):

yes, check please

OpenStudy (turingtest):

eh the evaluation is annoying let me just write it out here

OpenStudy (noelgreco):

I think that should be ln(21)

OpenStudy (turingtest):

what am i doing i will let wolfram do it

OpenStudy (turingtest):

yeah you are off somewhere I don't see how you got log(2) either

OpenStudy (turingtest):

I would just change the bounds and simplify the integral with a u-sub to avoid these kinds of errors

OpenStudy (noelgreco):

I get \[343 \ln 21 - \frac{ 1540 }{ 9 }\]

OpenStudy (ashley1nonly):

you were right. how did you get that. where do you think i messed up

OpenStudy (turingtest):

\[\int\limits_{1/3}^{7}14x\ln(3x)dx\\u=3x\implies dx=\frac13du\\\frac{14}3\int_1^{21}u\ln udu=\frac{14}3\left(u^2\ln u-\int_1^{21}udu\right)=\frac{14}3\left.\left(u^2\ln u-\frac12u^2\right)\right|_1^{21}\]evaluation is easier now

OpenStudy (ashley1nonly):

thanks, everyone give medals

OpenStudy (turingtest):

I have enough, Noel can have mine

OpenStudy (noelgreco):

\[(7*7^{2}\ln (3\times7)-\frac{ 7 }{ 2 }7^{2}\] Gee, I was still typing into the equation editor. By the way, Mr. Turing, what editor are you using?

OpenStudy (turingtest):

I use embedded latex do inline latex by enclosing commands with \.()\ do regular latex by enclosing in \.[]\ (take out the . in both cases) If you don't know what latex is, I'll try to find you a tutorial site

OpenStudy (turingtest):

we also have a latex practice group that can be found by clicking \(\href{http:///openstudy.com/study#/groups/LaTeX%20Practicing!%20%3A)}{here}\) (me showing off fancy tricks you can do with latex :P )

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