Recent content by Uniquebum

  1. U

    Multiple variable prediction interval

    Thanks a lot for the replies. I looked through a couple of books but they only talked about multiple variable regression in too vague manner. This'll help me get forward. Thanks again.
  2. U

    Multiple variable prediction interval

    Hey! I'm working with some regression related stuff at the moment and i'd need some help with multiple variable prediction interval. Prediction interval for a single variable can be calculated using PI = \hat{\beta_0}+\hat{\beta_1}x_i \pm t^* s_e \sqrt{1+\frac{1}{n} +...
  3. U

    Boltzmann equation with collision term

    Oh nice! Everything seems so much clearer now :). Thanks a lot Mute!
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    Boltzmann equation with collision term

    I'm somewhat familiar with the laplace transform and thus had it a go. I'll use "k" to replace that nu mark for the sake of convenience. Now \frac{\partial f(v,t)}{\partial t} + a \cdot \nabla_v f(v,t) = -k (f(v,t) - f_0(v)). What was probably clear before but what i didn't state, was that...
  5. U

    Boltzmann equation with collision term

    Homework Statement Solve the Boltzmann equation for a homogeneous plasma with not external forces present when the collision term is \frac{\partial f(v,t)}{\partial t} = -\nu (f(v,t) - f_0(v)), where \nu and f_0 are constants. Homework Equations Boltzmann equation \frac{\partial...
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    Probability question considering 6 dice throws

    Thanks alot! Got it done :). Final calculation being P(A n B) = 1 - (5/6)^6 - (5/6)^6 + (4/6)^6 = 0.41799... Anyway, thanks again!
  7. U

    Probability question considering 6 dice throws

    Homework Statement Dice is thrown 6 times. What's the probability of numbers 5 and 6 showing up at least once.Homework Equations This ought to be basic probability calculus but i just can't get my head around this. Some kind of attempt(ish) below. THe answer ought to be 0.418 or 41.8%.The...
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    Calculate Upper and Lower Sums for Variable Intervals

    I'm actually starting to wonder whether it might be a typo by my professor. Since it seems the function would only get one value if defined the way i stated in the original post. \frac{1}{n} right?... or?
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    Calculate Upper and Lower Sums for Variable Intervals

    Right, I gave it a wild shot and this is what i came up with. The upper sum is defined as \sum_{k=1}^{n}(x_{k+1}-x_k)*sup(f(x)) Now let's choose such width for the Riemann sum quadrilateral that 0.5*(\frac{1}{n} - \frac{1}{n+1})= \frac{1}{2n(n+1)} = r_n. Lets place each quadrilateral...
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    Calculate Upper and Lower Sums for Variable Intervals

    It actually is f(x)=\frac{1}{n}. Yea, I'm trying to approach this with Riemann sums and the intervals don't need to be equal in size as far as i understand.
  11. U

    Calculate Upper and Lower Sums for Variable Intervals

    Let f:[0,1]->ℝ and f(x) = \frac{1}{n} when x=\frac{1}{n²}, n=1,2,... and 0 in other case. Define such spacing/interval D that S_D-s_D < \frac{1}{100}. Here S_D refers to the upper sum and s_D the the lower sum.Now, I'm not sure how to approach this really since the sum is defined so that the...
  12. U

    Magnetic field in the middle of the plate

    I'd assume you need to use Biot-Savart's law and double integral to get it right.
  13. U

    Momentum question involving an elastic collision

    As you stated, momentum is conserved but so is one other thing. Can you figure out what?
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    Is the Diameter of the Open Ball B(0,r) equal to 2r?

    1. Prove that 0 is an upper bound of S=\{x\in \mathbb{R}|x<0\}. (OK, this step is trivial). 2. Prove that S=sup\{x\in \mathbb{R}|x<0\}\leq 0. (Also kind of trivial, if you think of what a supremum is). 3. Prove that S=sup\{x\in \mathbb{R}|x<0\}\geq -\epsilon for all \epsilon>0. 1) 0 is an...
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    Is the Diameter of the Open Ball B(0,r) equal to 2r?

    Righty, here we go again. We want to prove that for all ε>0, sup(d(x,y))>2r-ε. Let \epsilon>0 be arbitrary. Antithesis: sup(d(x,y)) \leq 2r-\epsilon This means that 2r-\epsilon is an upper bound of the set. Let \epsilon>\delta>0. Now 2r-\epsilon<2r-\delta<2r which means 2r-\epsilon cannot...
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