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Mathematics 20 Online
OpenStudy (zale101):

Trig. Sub?

OpenStudy (zale101):

\[\int\limits_{}^{} \frac{ \sqrt{x^2-9}}{ x} dx\]

hartnn (hartnn):

you're trying \(\Large x = 3 \sec u\) ? worth a shot

OpenStudy (zale101):

Here's what I tried to do \[x^2-9=9sec^{2}\theta-9=9tan^{2}\theta\]

OpenStudy (zale101):

\(x=3sec^{2}\theta\)

hartnn (hartnn):

not sec^2 you've tried x= 3 sec thetha

OpenStudy (zale101):

\[\int\limits_{}^{}\frac{ \sqrt{9\tan^{2}\theta} }{ 3\tan\theta }*3\sec^{2}\theta~dx\]

OpenStudy (zale101):

Oh my bad, i meant \(x=3sec\theta\)

hartnn (hartnn):

so denominator would be 2 sec thetha, roight ?

hartnn (hartnn):

*3 sec thetha**

OpenStudy (zale101):

Oh, makes sense ! >.< THanks @hartnn this mistake was small but ughhhh

hartnn (hartnn):

also be careful with your derivatives :)

OpenStudy (zale101):

Yes! :)

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