Recent content by paralian

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    Describe each plane, 8x-5y=-40z

    Apologies for this being a kind of stupid question... Homework Statement Describe each plane (a) 8x-5y=-40z Homework Equations Probably have to find the x, y, and z intercepts. The Attempt at a Solution I would assume that in order to find the x intercept you set y and z...
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    Magnetic Force on a Wire with a Changing Direction of Current

    I think the only part of the wire that matters is the part that isn't parallel to the magnetic field (ie from -6 to 0 along the x axis, which is perpendicular to the field).
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    Electric charge in a shell

    Homework Statement (Note: Don't worry about significant digits. I just want to be able to do the question and will worry about significant digits on the exam.) In the figure below, a non-conducting spherical shell of inner radius a=2.00cm and outer radius b=2.40cm has (within its...
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    Evaluating a Riemann Sum for $\int^{-2}_{5} t^2 + 6t - 4 dt$

    Sorry, I messed up the thing I meant for it to be from -2 to 5 but I put the numbers in the wrong places when I was typing it up :P Ok :) This is the "etc, etc." Where did I miss a "-" on the -4 ? lim \sum t^2 + 6t - 4 \Delta t lim \sum ( ( \frac{7i}{n})^2 + 6 \frac{7i}{n} - 4 )...
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    Evaluating a Riemann Sum for $\int^{-2}_{5} t^2 + 6t - 4 dt$

    [SOLVED] Riemann sum Important stuff: \sum i^2 = \frac{n(n+1)(2n+1)}{6} \sum i = \frac{n(n+1)}{2} And the solution: (Where I write "lim" I mean limit as n-->infinity. Where I write the summation sign I mean from i=1 to n.) lim \sum t^2 + 6t - 4 \Delta t \Delta t = \frac{5 -...
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    Calculating the electric field from the potential

    2.00yz^2 \frac{\partial x}{\partial x} =2.00yz^2 =-64 2.00xz^2 \frac{\partial y}{\partial y} =2.00xz^2 =96 2.00xy \frac{\partial z^2}{\partial z} =2.00xyz =-48 \sqrt{64^2 + 96^2 + 48^2} =125 The answer in the back of the book is 150 N/C.
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    Calculating the electric field from the potential

    Haha...yes. It's probably something really simple. I just don't know what to do to find each component
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    Integral with trig substitution

    Right...I always forget that! x=3*sec \theta \Rightarrow \theta = Sec^-1 (x/3) \Rightarrow tan\theta = \sqrt{x^2-9}/3 9 \sqrt{x^2-9} + (x^2-9)^\frac{3}{2} /3 Shiny! Thanks
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    Calculating the electric field from the potential

    Homework Statement What is the magnitude of the electric field at the point (3.00\hat{i} - 2.00\hat{j} + 4.00\hat{k})m if the electric potential is given by V = 2.00xyz^2, where V is in volts and x, y, and z are in meters? Homework Equations To calculate the field from the potential...
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    Integral with trig substitution

    27\int (1+\tan^2 \theta)\sec^2 \theta d\theta 27\int \sec^2 \theta d\theta + 27\int \tan^2 \theta\sec^2 \theta d\theta 27*tan\theta + 9\tan^3 \theta Haha sorry I kind of forgot that \int \sec^2\theta d\theta was tan!
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    How to Calculate Volume of a Rotated Graph Using the Shell Method?

    Ok...I think I get it. \int^{1}_{0}\pi (x^2)^2 dx = \pi*\int^{1}_{0}x^4 dx = \pi*(1^5/5-0) = \pi/5 Is that right?
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    How to Calculate Volume of a Rotated Graph Using the Shell Method?

    Would that end up being... \int^{1}_{0}(\pi r^2)dx where r = "Outer radius" (1) minus "inner radius" (x^2) ? (I hope so, I have a test tomorrow)
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    Integral with trig substitution

    [SOLVED] Integral with trig substitution Homework Statement Find \int(x^3)/\sqrt{x^2-9} Homework Equations Trig substitution. sin^2 + cos^2 =1, and other things that you can figure out from that. Half angle formula, cos^2\theta=(1+cos(2\theta) )*.5 The Attempt at a Solution...
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    Stargazing Catching the Eclipse Last Night: A Tale of Cold and Clear Skies

    Good pictures! I don't have a good camera (it's good enough usually) and it was kind of cloudy here, but oh well. It's just amazing that people in so many places were all watching it at the same time.
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