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0 votes
1 answer
77 views

how to write this region $D$ in relation to $r,\theta$ in this $\iint_Df(x,y)dxdy$ where $D=\{x^2+y^2 \le1,x+y\le 1\}$ and $D=\{x^2+y^2\le1,x+y\ge1\}$

I have attached two photos showing the integration bounds and I find it tricky how to express $r$ and $\theta$ in those two, if $x=r \cos{\theta}$ and $y=r\sin{\theta}$, so any help is very much ...
A Math Wonderer's user avatar
0 votes
0 answers
30 views

Triple Integral - Use symmetry for center of mass question?

I am unsure when to use symmetry with triple integrals. Can I use symmetry for this centre of mass question? $E$ is bounded by the parabolic cylinder $z=1-y^2$ and the planes $x+6z=6, x=0$, and $z=0 ; ...
user41592's user avatar
  • 143
0 votes
1 answer
41 views

Triple integral (mass) - setting up region between planes and parabolic cylinder

I am trying to set up the following triple integral using the xy plane. $E$ is bounded by the parabolic cylinder $z=1-y^2$ and the planes $x+6z=6, x=0$, and $z=0 ; \quad \rho(x, y, z)=8$. I set up ...
user41592's user avatar
  • 143
0 votes
1 answer
26 views

Double integral: technique to derive the limitations of $y$ (or $x$)

$$\iint_Cy dxdy, \quad C=\{(x,y)\colon0\leqslant x\leqslant2+y-y^2\}.$$ It is simple to see $x=2+y-y^2$ is a parabola with the symmetry axes is $x$ and the vertex $(9/4,1/2)$. It is easy to find the ...
Sebastiano's user avatar
  • 7,792
0 votes
1 answer
92 views

How does one calculate the area of a set?

The set is $M=\{(x,y)\in\mathbb{R}^2:|x|+|y|\leq 1\}$. Question: How do you calculate the area of $M$? More specific, how do you find the bounds of integration? Attempt: I tried to solve the ...
Jowo's user avatar
  • 1
1 vote
0 answers
106 views

Changing the Order of Integration in a Triple Integral

I'm currently studying for my multivariable calculus exam and I've come across a problem that I can't seem to solve. I have a triple integral with the order of integration $dz \, dy \, dx$ and I need ...
AtomicZ's user avatar
  • 11
2 votes
2 answers
113 views

Double integral of $1/(x^2+y^2)$ restricted to $x^2+y^2\leq2$ and $x\leq1$

Find $$\iint_D \frac{1}{(x^2+y^2)^2}dA$$ where $$D = \left\{ (x,y): x^2 + y^2 \leq 2 \right\} \cap \left\{ (x,y): x \geq 1 \right\}$$ Because of the prevalence of $x^2+y^2$ terms here, I figured we ...
wesmlr's user avatar
  • 23
1 vote
0 answers
44 views

Integral bounds for $x\geq yz$

I am having trouble understanding the integral bounds. From what side should my understanding go (first or second?): first: as $z$ is between zero and one, $y$ is also between zero and one, thus $x$ ...
VLC's user avatar
  • 2,527
1 vote
1 answer
64 views

Why does changing integral bounds get me the wrong answer?

Full disclaimer, this is a homework question. While solving this question, I came upon the integral $$\int_{-r}^{r}\frac{b\tan^{-1}(\theta)}{2}\sqrt{r^2-x^2} dx$$ Proceeding with trig substitution I ...
Andrew Wang's user avatar
3 votes
3 answers
481 views

Help me understand easy (not for me) concepts in volume integral

Keep looking at the page for an hour. Still not sure how I can get the sloping surface of $x+y+z=1$ and integration ranges for $x, y, z$. and why their range is different too. The book keeps throwing ...
user avatar
0 votes
2 answers
419 views

Double integral setup - Uniform distribution

I am currently trying to understand a specific component of a probability problem involving setting up the proper bounds on a double integral. In the problem, $X_1$ and $X_2$ are independent Uniform $(...
John Coltrane's user avatar
3 votes
3 answers
889 views

$\iiint_M (x+y+z)\,dx\,dy\,dz$ over $M=\{(x,y,z)\in\mathbb{R^3}: 0≤z≤(x^2+y^2)^2≤81\}$

$$\iiint_M (x+y+z)\,dx\,dy\,dz$$ over $M=\{(x,y,z)\in\mathbb{R^3}: 0≤z≤(x^2+y^2)^2≤81\}$. How would I express this with the correct bounds? Once I have the bounds I can continue on my own but I need ...
Acyex's user avatar
  • 487
1 vote
1 answer
1k views

Determining Bounds of Theta for Double Integration of a Polar Region

Given the region $$ R:(x, y | x^2 + y^2 \le 4x) $$ And given the function $f(x, y) = \frac{x}{\sqrt{x^2+y^2}}$, find the double integral of the polar region. So upon sketching the graph we get a ...
Stephen's user avatar
  • 11
0 votes
0 answers
26 views

Correct limit of integration when it difficult to visualize the region of integration?

I was running into a problem where I need to evaluate some probability over a region $D$. A toy example would be this probability $\Pr \left[ {\underbrace {Y < \frac{{5\left( {X + 7} \right)}}{{9X}}...
Tuong Nguyen Minh's user avatar
0 votes
0 answers
26 views

Is this the correct intersection between the two integration region?

My research require me to integrate this separable function $f\left( {x,y,z,t} \right) = f\left( x \right)f\left( y \right)f\left( z \right)f\left( t \right)$ over the region $D = {D_1} \cap {D_2}$ ...
Tuong Nguyen Minh's user avatar

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