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Mathematics 20 Online
OpenStudy (kaiz122):

integrate this one please......

OpenStudy (kaiz122):

\[\int\limits_{}^{} \frac{\sqrt{x}+5}{\sqrt{x}-2} dx\]

OpenStudy (anonymous):

I think you should prefer Rationalization here..

OpenStudy (kaiz122):

yes, please, i have my answer but i checked it by differentiation, and i got a wrong answer, i want know where is my mistake

OpenStudy (anonymous):

You should show your work so that we can find where you have done wrong..

OpenStudy (kaiz122):

ok,

OpenStudy (anonymous):

Need not to be fast.. Take your time..

OpenStudy (kaiz122):

oh, it's alright now, i saw where i've done wrong. thanks though. :)

OpenStudy (anonymous):

Sure??

OpenStudy (kaiz122):

help me again please. @waterineyes

OpenStudy (anonymous):

Where??

OpenStudy (kaiz122):

can you show me how you solve it? i'm confused

OpenStudy (anonymous):

I said you to use rationalization here.. Multiply and divide by \(\sqrt{x} + 2\)..

OpenStudy (anonymous):

just take \[\sqrt{x}=t\]

OpenStudy (anonymous):

write, \[\sqrt{x}+5=\sqrt{x}-2 +3\]

OpenStudy (anonymous):

that means x=t^2 and dx=2tdt

OpenStudy (anonymous):

then the integration becomes, \[(1+3/t-2 )2tdt\]

OpenStudy (anonymous):

i think you can go ahead from here?

OpenStudy (kaiz122):

ok, thanks. :)

OpenStudy (anonymous):

rationalize it will get easy .

OpenStudy (anonymous):

@sami-21 i think rationalising makes it a lil difficult.never mind. thats my opinion

OpenStudy (kaiz122):

after having \[2\int\limits_{}^{} \frac{u^2 +5u}{u-2} du\] what shal i do? i tried using long division, and after that,

OpenStudy (kaiz122):

@vamgadu @waterineyes

OpenStudy (anonymous):

stick with the long division, that's the way to go.

OpenStudy (anonymous):

How did you get it??

OpenStudy (anonymous):

you should get something like that. \[ u+7+\frac{14}{u-2}\]

OpenStudy (kaiz122):

i got \[2\int\limits_{}^{} (u+7+\frac{14}{u-2}) du\]

OpenStudy (anonymous):

Separate them..

OpenStudy (kaiz122):

then i got \[u^2 +14u+28 \ln |u-2|+ C\]

OpenStudy (anonymous):

Absolutely...

OpenStudy (anonymous):

What else you want?? This is the answer dude..

OpenStudy (anonymous):

not quiet, back substitution

OpenStudy (kaiz122):

if i substitute \[\sqrt{x} =u\]

OpenStudy (anonymous):

Of if you made any substitution then replace u by that..

OpenStudy (kaiz122):

i got \[x +14\sqrt{x} +28 \ln |\sqrt{x} -2| +C\]

OpenStudy (anonymous):

Right.. Well done..

OpenStudy (kaiz122):

but if i get the dervative of it, i should have obtained the problem, but i don't.

OpenStudy (kaiz122):

oh, i got it already. when i get the derivative of x i thought it was 0, it should be 1, thanks to you all!! :)

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