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    Asteroids momentum

    An asteroid is spotted moving directly toward the center of Starbase Alpha. The frightened residents fire a missile at the asteriod, which breaks it into two chunks, one with 2.4 times the mass of the other. The chunks both pass the starbase at the same time. If the lighter chunk passes 1800 m...
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    Ideals in the ring Q[X]

    Consider the ideal I of Q[x] generated by the two polynomials f = x^2+1 and g=x^6+x^3+x+1 a) find h in Q[x] such that I=<h> b) find two polynomials s, t in Q[x] such that h=sf+tg
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    Linear Algebra question: n x n determinants

    Call the upper non-zero submatrix for U and the lower for L. Then the determinant is the product of their determinants, i.e det(U)det(L)
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    Normal Distribution

    Why even use a binomial approximation? Let Y denote the number of computer chips whose lifetimes are less than 1.8*10^6. Then Y~Bin(100, 0.9082).
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    Parabolic cylindrical coordinates

    Can someone, please, show me an example of when you are better of with parabolic cylindrical coordinates than with cartesian coordinates when computing a triple integral over a solid?
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    Massless particle revolving in a circle

    You tell me. I have no clue what they are asking. :cry:
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    Massless particle revolving in a circle

    Given: A massless particle revolving in a circle with a rotational velocity = (2+sin(a)) To Find: Y-axis acceleration Method #1 (from rotational acceleration) Y-axis acceleration = (2+sin(a))(cos(a))^2 Method #2 (from Y-axis velocity) Y-axis acceleration =...
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    Confused on finding Eigenvalues and Eigenvectors

    See" [Broken].
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    Limit of Trig Function

    scorpa, don't be so harsh on yourself. :wink:
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    Limit of Trig Function

    \cos \left( {2x} \right) = \cos ^2 x - \sin ^2 x = (cos x - sin x)(cos x + sin x) does it ring a bell now? You have to do something with the numerator.
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    Partial integration help

    How I started first? I tried with partial integration in many different ways.. :bugeye:
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    Partial integration help

    How do I integrate: [tex]\frac{xarctan(x)}{(1+x^2)^2}[/itex]
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    Calculating intercept with x-axis

    Use the" [Broken] on a)
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    I hate it when people prounce ln as lawn" [Broken] (scroll down a bit)
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    I hate it when people prounce ln as lawn

    Yes. Take a look at". You can even click on the sound button to hear how it's pronounced.
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    I hate it when people prounce ln as lawn

    Well... Here in Sweden "root of two" implicitly means "square root of two" since square root is the most ordinary root.
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    Why is this limit of 2 variables undefined? it looks like both = 0!

    To prove that lim f(x,y) does not exist, it suffices to show that the limit along one curve into (a,b) differs from the limit along a second curve. If lim f(x,y) does exist, however, then computing limits along individual curves will prove nothing (although, such computations will likely help to...
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    Why is this limit of 2 variables undefined? it looks like both = 0!

    You can show that the limit is undefined by showing that the limit depends on how you approach zero. You can show that f(x,y) \longrightarrow \frac{1}{2} if you approach zero along the curve (\sqrt{y},y). So you have showed that the limit is both 0 and 1/2, i.e. it must be undefined.
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    I hate it when people prounce ln as lawn

    Had a prof in math who pronounced it squirt too :biggrin:
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    Conditional Probability Traffic light question

    Hint:" [Broken]. Just use the formula.
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    Find instantaneous rate of change of 7/3z^2

    Just" [Broken] it with respect to z.
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    What is the derivative of y=sin(x+y)?

    The partial derivatives of f(x,y) = sin(x+y) are \frac{df}{dx} = cos(x+y) and \frac{df}{dy} = cos(x+y)
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    Lim f(0,y). y->0. L'H rule needed, did i do it right?

    You seem to have misunderstood L'Hospitals rule. L'Hospitals rule states that \lim \frac{f(x)}{g(x)} = \lim \frac{f'(x)}{g'(x)} if \lim f(x) and \lim g(x) are both zero or ±\infty. L'Hospitals rule isn't necessary. Just use the standard limit for \frac{sin(x)}{x}
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    Linear Algebra Proof

    Yes, you could say that. :smile:
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    Linear Algebra Proof

    They are just using the assumption A = 2A^T in that step.
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    Linear Algebra - Basis

    The general equation of a plane is Ax+By+Cz = D. D = 0 \Longleftrightarrow the plane goes through the origin.
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    Algebra help!

    You are done! You just showed that I-T is invertible/bijective by showing that (I-T)(I+T) = (I+T)(I-T) = I. Which means, by definition, (I-T)^{-1} = (I+T)
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    Adding consecutive squares?

    Dr. Math has answered a lot of questions concerning the sum of consecutive squares here. He explains that there are several ways to derive the formula.