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2 votes
2 answers
106 views

Find the exact length of the parametric curve(Not sure what I'm doing wrong)

As the title says, I'm not sure what I'm doing wrong. Any help would be greatly appreciated. Here's the problem with my solution. Find the exact length of the parametric curve $(x,y)=(\theta+\...
Timmy Wick's user avatar
1 vote
0 answers
58 views

Prove that if $V=\text{constant}$ then the second part in the paratheses after the integral sign is equal to $0$

$$\frac{\mathrm d}{\mathrm dt^i} \underset{\large V(t)}{\iiint} \Psi \,\mathrm dV= \underset{\large V(t)}{\iiint} \left({\frac{\partial \Psi}{\partial t}+\nabla\cdot\Psi\mathbf v_i}\right)\, \mathrm ...
Victor's user avatar
  • 8,382
0 votes
1 answer
375 views

Area under a basketball shot

The other day, someone asked me how to find the area under a basketball shot. It looked something like this: How would I go about doing this?
user avatar
2 votes
1 answer
4k views

Area bounded by$ y^2=x^2(1-x^2)$

Find the area bounded by $y^2=x^2(1-x^2)$? I think in this way as the graph lies between -1 to 1 the area is 4 times of $\int x \sqrt{1-x^2} dx$ limits from 0 to 1. Am I correct?
sai saandeep's user avatar
  • 1,144
1 vote
1 answer
246 views

Work problem - chain hanging on the ground

I am a bit tripped up on the following work problem -- A 30 ft long chain is hanging from one end on a hook, 25 feet above the ground; naturally, this means 5 feet of the hook are on the ground ...
jimhacklebarth's user avatar
1 vote
4 answers
2k views

What is the exact role of the integrals in a PID Controller?

I am trying to understand the function of a PID Controller. It returns a value, which is the sum of three components. The proportional, derivative and integral components. I am having issues grasping ...
Saturn's user avatar
  • 7,211
2 votes
4 answers
1k views

How does Volume work with integration?

Using a cross section suppose, as described here: Area formula Paul Notes Suppose this is: $y = f(x)$. He says the volume is: $$\int_{a}^{b} A(x) dx$$ But how does area over that interval give ...
Amad27's user avatar
  • 11.2k
2 votes
0 answers
111 views

Application of integrating $\cos^4 x$?

A student asked a colleague the other day for a practical application that involved needing to integrate the fourth power of cosine, but no one here could think of one off-hand other than some volume ...
Ms. H.'s user avatar
  • 21
6 votes
1 answer
2k views

Volume vs. Surface Area Integrals

In order to find the volume of a sphere radiud $R$, one way is to slice it up into a stack of thin, concentric disks, perpendicular to the $z$-axis. a disk at any point $z$ will have radius $r=\sqrt{R^...
Dylan's user avatar
  • 16.6k
0 votes
0 answers
2k views

Volume enclosed by two spheres (triple integral, cylindrical coordinates)

The question: Find the volume of the solid enclosed by the sphere $x^2 + y^2 + z^2 - 6z = 0$ , and the hemisphere $x^2 + y^2 + z^2 = 49 , z ≥ 0$ I set up the triple integral $\int_0^{2\pi}\...
user2847441's user avatar
0 votes
1 answer
52 views

Finding the work using integrals

A tank full of water has the shape obtained by revolving the curve $y = arcsin(x)$ around the y axis from $x = 0$ to $x = 1$. Find the work required to pump the water out of the tank. (The density of ...
John's user avatar
  • 25
0 votes
2 answers
963 views

"Present value and accumulated value of money flow" problem

Find the present value and accumulated value after 10 years for an income stream with the rate of money flow $f(t) = 200 + 150t$ dollars per year and the rate of interest 12% compounded continuously. ...
arcbloom's user avatar
  • 2,062
1 vote
1 answer
3k views

Optimisation of a rectangles area under a function curve

I have a questions asking for the dimensions of the rectangle with the largest area that has two bottom corners on the x axis and two top corners on the curve $y=12-x^2$. I have plotted the curve and ...
user88720's user avatar
  • 507
6 votes
2 answers
999 views

Applications of integrals of rational functions of sine and cosine

I earlier asked this question about conformal equivalence of flat tori with embedded tori. In the ensuing thread the integral $\displaystyle\int\frac{dx}{R+\cos x}$ occurred. If I'm not mistaken, it ...
Michael Hardy's user avatar
1 vote
1 answer
2k views

Engineering Application with Integration

(source: gyazo.com) I need help for part $(i)$ ... What I think I know so far: $P = dgh = (1000)(9.8)(h)$ Finding $h$: We will choose an arbitrary value '$x$' somewhere between $0$ and $3$. The ...
EngGenie's user avatar
  • 215

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