Search results

  1. I

    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
  2. I

    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)
  3. I

    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).
  4. I

    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?
  5. I

    Confused on finding Eigenvalues and Eigenvectors

    See http://mathworld.wolfram.com/CharacteristicEquation.html" [Broken].
  6. I

    Limit of Trig Function

    scorpa, don't be so harsh on yourself. :wink:
  7. I

    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.
  8. I

    Partial integration help

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

    Partial integration help

    How do I integrate: [tex]\frac{xarctan(x)}{(1+x^2)^2}[/itex]
  10. I

    Calculating intercept with x-axis

    Use the http://mathworld.wolfram.com/Mean-ValueTheorem.html" [Broken] on a)
  11. I

    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...
  12. I

    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.
  13. I

    Find instantaneous rate of change of 7/3z^2

    Just http://mathworld.wolfram.com/Derivative.html" [Broken] it with respect to z.
  14. I

    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)
  15. I

    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}
  16. I

    Linear Algebra Proof

    Yes, you could say that. :smile:
  17. I

    Linear Algebra Proof

    They are just using the assumption A = 2A^T in that step.
  18. I

    Linear Algebra - Basis

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