Recent content by Xishem

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    How to find the absolute extrema of a function on a given interval?

    Ok. First, what is: \frac{d}{dx} (-x^3+3x)
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    How to find the absolute extrema of a function on a given interval?

    Your derivative is incorrect. Specifically, this part: \frac{d}{dx}3x
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    Help with a triple integral in spherical coordinates

    [Edited out various confusions] ... I think I found the issue. Your definition of dV is inconsistent with your angle definitions. It should be dV=r^2 sin\phi\ dr\ d\theta\ d\phi
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    Help with a triple integral in spherical coordinates

    Everything seems ok to me. Why do you say that equals 0?
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    Help with a triple integral in spherical coordinates

    Multiplication is commutative, so your differential quantities can be multiplied and any order and will still be correct. You're missing some non-differential terms out front of your expression. Edit: Ninja'd
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    How Do You Correctly Derive (-x^2/18)?

    The derivative of a constant is 0.
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    Product Rule Derivative Problem

    Between lines 3 and 4 of your work you incorrectly simplified the first term like this: t^{\frac{1}{2}}(-2t)=-2\sqrt tOtherwise, I agree with your work.
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    How Do You Correctly Derive (-x^2/18)?

    Let's try this first: What is \frac{d}{dx}x^2 ?
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    How Do You Correctly Derive (-x^2/18)?

    You're using the power rule incorrectly also. The power rule is: \frac{d}{dx}cx^n=ncx^{n-1}Edit: Ah, it looks you are trying to do the product rule. Remember that if you have any constant times x or x divided by a constant, you can use the power rule instead of the product or quotient rules...
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    How Do You Correctly Derive (-x^2/18)?

    Instead of using the quotient rule, try writing the function as: \frac{1}{18}x^2 Now it is just a power rule derivative. Does that help? Not that the quotient rule doesn't work, though. From your answer, it looks like you're doing it incorrectly. Remember that the quotient rule is...
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    Volume of Frustum Using Triple Integration

    Volume of Frustum Using Triple Integral [Solved] Homework Statement Edit: I've solved the issue! My limits of r were wrong. Instead of this: V=\int_{z=0}^{\frac{h}{2}}\int_{r=0}^{\frac{R}{h}z+R}\int_{\theta=0}^{2\pi}r\ d\theta\ dr\ dzIt should have been this...
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    Adding vectors algebraically for football runner

    The object is originally headed on a vector of 270°. It changes course by -25° from 270°. Thus, the angle should be labeled from the 270° axis to the vector of the newest direction. You should be able to visually see that the angle you labeled in the OP is not 25°, as it is clearly obtuse.
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    Relative angular velocity of a satellite

    If Earth did not rotate, one day would be the same as one year. One day is generally accepted as the time it takes for the Earth to perform a full rotation. If the Earth did not rotate, one full revolution around the sun would simulate a normal 24-hour day as far as the sun's motion relative to...
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