Recent content by CallMeShady

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    Double Integration without Anti-Derivatives

    I can calculate the area exactly without rotation; however, I could not think of a way to find the centroid of the triangle in the given orientation in the question. Hence, by making a simple rotation, it just made my life easier.
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    Double Integration without Anti-Derivatives

    And as haruspex mentioned, the formula I was using did not rotate the co-ordinate counterclockwise. A quick Google search led me to the correct formula, and now I can satisfyingly say that I found the correct answer: I = -7.027811891 It's off by 0.01 from one of the answers, but that should be...
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    Double Integration without Anti-Derivatives

    The centroid co-ordinates are (1.110899311, 0.555130063). The first co-ordinate is for the base. Basically what I did was position the right triangle's base on the x-axis, and then find the centroid co-ordinates of it. Then I rotated the triangle by 26.5 degrees counter clockwise in order to...
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    Double Integration without Anti-Derivatives

    http://i62.tinypic.com/zxtvsx.jpg Might be hard to read, but maybe it may be visible enough? Please click on the image, and then select the option (view raw image) to zoom in.
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    Double Integration without Anti-Derivatives

    Ahhhhh this is going to make me have nightmares tonight! So I found a calculation error in determining the height of the right triangle, so I re-did all the calculations with the correct values. I got an answer of -2.29. It's not one of the answers. Then I rounded my values of base, height, and...
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    Double Integration without Anti-Derivatives

    Interesting stuff. So I broke up the integral and recognized this: I = a∫∫dA + b∫∫xdA + c∫∫ydA. The first terms is simple "a" times the area, the second term is the centroid of x times the area times b, and the last terms is the centroid of y times the area times c. My centroid points appear...
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    Double Integration without Anti-Derivatives

    Well, for a right triangle, it's simple as the formulas are already dervided online. Or, we could simply integrate using (assuming density is constant): x_centroid = 1/A * ∫∫x*dA y_centroid = 1/A * ∫∫y*dA Suppose I do find the centroid co-ordinates, how does that result into determining a...
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    Double Integration without Anti-Derivatives

    No, I don't recognize this from any of my courses. I was able to follow through the logic that you presented. However, shouldn't it be ##\vec{u} = (b,c)##? Also, when you break the integral into two in the end, don't I still have to use anti-derivatives for the second piece in x and y (as...
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    Double Integration without Anti-Derivatives

    Well, I am still a bit confused as to where to go from here. After reading the responses and doing some research online, I stumbled upon something called the "Jacobian." Am I drifting off on a tangent to infinity?
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    Double Integration without Anti-Derivatives

    Yes, the values are correct (as shown in my question). Althought I must point out that two previous questions have had incorrect sets of answers in this particular problem set. My professor acknowlegded them as well.
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    Double Integration without Anti-Derivatives

    Hm... it represents a plane. Are you suggesting that I find the volume of the two pieces (triangular base + another triangular piece on top with the slanted plane)?
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    Double Integration without Anti-Derivatives

    Unfortunately, I don't quite understand the idea that you are suggesting. I am unsure on how switching two co-ordinates will achieve anything in regards to this problem.
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    Double Integration without Anti-Derivatives

    Homework Statement Make a good sketch of the plane region D defined by the following simultaneous inequalities: D: y >/= -2x, 2y >/= x, 2y </= 4-x. Use deep conceptual understanding the insight (and no antiderviative calculations!) to reduce the iterated integral below to a simple algebraic...
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    Deriving Efficiency of a Diesel Engine Formula

    Homework Statement The Diesel cycle is an idealized representation of the process that occurs in a Diesel combustion engine, as shown in the graph below. Starting at point a, the Diesel cycle consists of an adiabatic compression, an isobaric expansion, and adiabatic expansion and an isochoric...
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    Finding Force Given Potential Energy

    I am not sure what you mean with that equation above... what does the hat above the variables mean? After substituting the numbers, I got r = √35 and plugging that into the original derived equation, I got an answer of -7.997 \times10-6 (which I am assuming is an answer in Newtons).
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