Ask your own question, for FREE!
Mathematics 12 Online
Vocaloid (vocaloid):

I'm a bit rusty with integration - question below

Vocaloid (vocaloid):

\[\int\limits_{ }^{ } \frac{ 4x }{ x^2 + \frac{ 1 }{ x } }\]

Vocaloid (vocaloid):

don't want a direct answer, I just want to know where to start

Vocaloid (vocaloid):

*should be a dx added into the equation

zepdrix (zepdrix):

It looks like it might be a simple u-substitution hidden in disguise. Try multiplying top and bottom by x, what happens?

Vocaloid (vocaloid):

\[\int\limits_{ }^{ }\frac{ 4x^2 }{ x^3 + 1 }\]

Vocaloid (vocaloid):

so I'm guessing I would let u = x^3 + 1 then that gives me du = 3x^2

OpenStudy (sweetburger):

yes, perfect

OpenStudy (coolor):

*du=3x^2(dx)

zepdrix (zepdrix):

Bottom is a cubic, top is a square, hmm that works out nicely! :)

OpenStudy (coolor):

^`

zepdrix (zepdrix):

\[\large\rm du=3x^2dx\]You could take a couple simple steps and turn the 3 into a 4 so it matches up perfectly with your numerator.

Vocaloid (vocaloid):

right, multiply by 4/3

Vocaloid (vocaloid):

(4/3)*ln(x^3+1)?

zepdrix (zepdrix):

Yayyy good job \c:/

OpenStudy (coolor):

don't forget the constant "c"

Vocaloid (vocaloid):

thank you both, I just started differential equations >>

zepdrix (zepdrix):

Ooo fun stuff!

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!