Ask your own question, for FREE!
Mathematics 7 Online
OpenStudy (dls):

Integrate!

OpenStudy (compassionate):

\[\int\limits_{a}^{b} = 2\]

OpenStudy (dls):

\[\Huge \int\limits_{0}^{100} \left\{ x \right\}dx\]

OpenStudy (dls):

its fractional x

OpenStudy (anonymous):

\[\{x\}=x-\lfloor x\rfloor=\begin{cases}x&\text{for }0\le x<1\end{cases}\] and \(\{x-n\}=\{x\}\) for \(n\in\mathbb{Z}\). So, \[\int_0^{100}\{x\}~dx=100\int_0^1x~dx\]

OpenStudy (dls):

didn't quite get it..

OpenStudy (anonymous):

Wait so \[ \{x\} = x-\lfloor x \rfloor \]?

OpenStudy (dls):

yes

OpenStudy (dls):

\[\LARGE 0.21=2.21-[2.21]=2.21-2=0.21\]

OpenStudy (anonymous):

Well, \[ \int_0^1\{x\} dx=\int_0^1 x-\lfloor x \rfloor dx =\int_0^1 xdx = x^2\Bigg|_0^1 \]Right?

OpenStudy (anonymous):

\[ \int_1^2\{x\} dx=\int_1^2 x-\lfloor x \rfloor dx =\int_1^2 x-1\;dx = \int_0^1udu=u^2\Bigg|_0^1 \]Where \(u=x-1\)

OpenStudy (anonymous):

You keep doing this \(100\) times...

OpenStudy (dls):

\[\int\limits_0^1 x-\lfloor x \rfloor dx =\int\limits_0^1 xdx = x^2\Bigg|_0^1\] How did this happen?

OpenStudy (ash2326):

@DLS So we have \[\int\limits_0^{100} x-\lfloor x \rfloor dx \] Let's break the limit from 0 to 1, we have \[\int\limits_0^{1} x-\lfloor x \rfloor dx \] Now tell me, if you have x between 0 to 1 floor of x would be ?

OpenStudy (ash2326):

@DLS are you here?

OpenStudy (dls):

extremely sorry! D: and it would be 0,but still why are we breaking the limit like this?

OpenStudy (anonymous):

|dw:1378658537164:dw|

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!