Recent content by Tom McCurdy

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    Testing whether one mean is higher than another

    There was a problem that was talked about in class where we had the amount of quantity sold in one column and the promotion level in another column. The promotion took values between 0 and 0.88 with a number of values being zero. The problem discussed was to test the following hypothesis The...
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    Engineering In serious need of a/c circuits help

    should probably show some attempt, and put this in the engineering forum
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    Inequality Proof: Showing \left|ab\right|\leq\frac{1}{2}(a^{2}+b^{2})

    Here was the way I thought about it: |ab| \leq \frac{1}{2}(a^2+b^2) times by 2 and square both sides 4a^2b^2 \leq (a^2+b^2)^2 0 \leq a^4 - 2a^2b^2 + b^4 0 \leq (a^2-b^2)^2 and since it is squared it must be greater than or equal to zero
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    Torsion - Coupling connecting two shafts

    Could someone maybe move this to the ME section?
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    Torsion - Coupling connecting two shafts

    Homework Statement There is a coupling attached two two shafts. The shafts have opposing and equal torques on them with a radius, r. Assuming the shear stress in the bolts used in the coupling is uniform, figure out how many bolts would be needed to make the max sheer stress in the shaft equal...
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    Determining Maximum bending moment via shear force diagram

    Homework Statement http://imagebin.ca/img/uzuDsi.jpg and by maximum it means in magnitude Homework Equations I figured the best (easiest/quickest) method would be to draw the shear force diagram. When I originally did this problem I came up with equations for M and V by dividing...
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    Understanding Total Derivative: Step-By-Step Guide

    Hi I was hoping someone could explain how this works to me I ran across this example in a book D(p(a)) = S(p(a),a) Total derivative with respect a \frac{dD(p(a))}{dp} \frac{dp}{da}= \frac{\partial S(p(a),a)}{\partial p} \frac{dp}{da} + \frac{\partial S(p(a),a)}{\partial a}
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    Know any good Semiconductor/Integrated Circuit dvds?

    Hi, I was hoping to get a video on how integrated circuits/semiconductors are made. I remember in an interview with a guy from KLA tencor a ways back the guy suggested a video. I can't remember what he said... though. It may have had the word ghost or something... although that's probably not...
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    Does the divergence theorem work for a specific vector field?

    oh shoot i forgot to say it is bounded by the cylinder z=0 z=4 r=2 my thought process from the surface integral was i found ds in r direction or the surface area normal to r 16 pi and surface area normal to z and doted it with E
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    Finding Vector Components of A and B in Spherical Coordinates

    the thing is I still don't have an answer to a, so its hard for me to know what you mean
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    Does the divergence theorem work for a specific vector field?

    Homework Statement Show divergence theorem works For the vector field E = \hat{r}10e^{-r}-\hat{z}3z Homework Equations \int_{v}\nabla \cdot E dv = \oint_{s} E \cdot ds The Attempt at a Solution \nabla \cdot E = 1/r \frac{d}{dr}(rAr)+1/r\frac{dA\phi}{d\phi}+\frac{dAz}{dz}...
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    Finding Vector Components of A and B in Spherical Coordinates

    wouldn't you just get vector B pointing the other way i am not sure what you are hinting at
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    Finding Vector Components of A and B in Spherical Coordinates

    Homework Statement I have a vector A and B in spherical coordinates, and I need to find: part a) The vector component of B in the direction of A. part b) The vector component of B perpendicular to A Homework Equations dot product cross product The Attempt at a Solution...
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    Causal Systems: Understanding the Basics

    We have been going over causal systems and I am still having trouble determining what defines a system to be causal. I was told that if the input is anything besides x(a*t) where a=1 then the system is non causal. I can kind of see this, but it is still a bit blurry for me. I also was...
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    Constructive and Destructive Interference of Waves at pi/50 Time - Find Points

    Homework Statement y1(x,t)=4*cos(20*t-30*x) y2(x,t)=4*cos(20*t+30*x) set t=pi/50 and find the points where the wave interferes constructively and destructivelyThe Attempt at a Solution So I tried to take the derivative of y1 and y2 added together and set it equal to zero. 120*sin(\frac{2...
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