Recent content by kpoltorak

  1. K

    Introductory Differential Equations Question

    Thank you everyone for being a source of help in previous problems I've posted here. I'm starting an intermediate course in Differential Equations and I'm enjoying it so far, but this one problem on my homework seems to be giving me a problem and I think that I haven't fully grasped the...
  2. K

    Can someone Please help me understand E(X) expected values in statistics

    Say you have two die D_1 and D_2. If one of them comes up as 1 and the other comes up as n then min{D_1,D_2} is always going to be 1. This is because the minimum of 1 and any other number has to be 1 because you can't roll lower than 1!
  3. K

    Group of order 100 with no element of order 4?

    Yes I do have some knowledge of direct products. Could I construct a group as such: \mathbb{Z}_{5}\times\mathbb{Z}_{5}\times\mathbb{Z}_{2}\times\mathbb{Z}_{2}?
  4. K

    Group of order 100 with no element of order 4?

    [b]1. Homework Statement [/] Is there a group G with order 100 such that it has no element of order 4? How would one go about proving the existence of such a group? [b]2. Homework Equations [/] For every prime divisor p of a group, there exists an element with order p. The...
  5. K

    Inequality Proof: Showing \left|ab\right|\leq\frac{1}{2}(a^{2}+b^{2})

    I think I see...? |ab|\leq\left|\frac{1}{2}(a^{2}+b^{2})-\frac{1}{2}(a+b)^{2}+\frac{1}{2}(a+b)^{2}\right| \left|ab\right|\leq\left|\frac{1}{2}(a^{2}+b^{2})\right| \left|ab\right|\leq\frac{1}{2}(a^{2}+b^{2})
  6. K

    Inequality Proof: Showing \left|ab\right|\leq\frac{1}{2}(a^{2}+b^{2})

    Right I've noticed that the values on both sides of the minus sign are all positive, however that doesn't necessarily mean that \left|ab\right| is less than \frac{1}{2}(a^{2}+b^{2}). Because its an absolute value, the LHS of the minus sign could be smaller than the RHS while preserving the...
  7. K

    Inequality Proof: Showing \left|ab\right|\leq\frac{1}{2}(a^{2}+b^{2})

    Homework Statement Show that \forall a,b \in R: \left|ab\right|\leq\frac{1}{2}(a^{2}+b^{2}) Homework Equations Triangle Inequality seems to be useless. The Attempt at a Solution (a+b)^{2}=a^{2}+b^{2}+2ab 2ab=(a+b)^{2}-(a^{2}+b^{2})...
  8. K

    General Formula for Multiplying Polynomials?

    Homework Statement Does a general formula exist? \sum \limits_{k=0}^{m_1} a_kx^k\cdot\sum \limits_{k=0}^{m_2} b_kx^k=\sum \limits_{k=0}^{m_1+m_2} c_kx^k Homework Equations The Attempt at a Solution I am having trouble understanding the relation between the c coefficients in the product and...
  9. K

    If A is contained in B, then the interior of A is contained in B.

    Thank you everybody for your help, I believe I have enough information to solve the problem.
  10. K

    If A is contained in B, then the interior of A is contained in B.

    Apparently not in this particular piece of literature (my homework): http://www.stat.psu.edu/~arkady/403/HWKs/Assignment%205.pdf" See Problem C.
  11. K

    If A is contained in B, then the interior of A is contained in B.

    I believe I have found an answer. \forall{X}\in{\tau}:X=X^{\circ} Where X^{\circ} is the interior of X, and \tau is a topological space. Doing some reading I found a definition of a topology which defines it as a collection of open sets, and then a definition which said that a set is open iff it...
  12. K

    If A is contained in B, then the interior of A is contained in B.

    Sorry, my original post was not entirely correct. I need to prove that the the interior of A is a PROPER subset of the interior of B.
  13. K

    If A is contained in B, then the interior of A is contained in B.

    The interior of Q is empty, and I believe the interior of R would be R if the topology is in R.
  14. K

    If A is contained in B, then the interior of A is contained in B.

    Homework Statement Given that A and B are in a topology, show that if A is contained in B, then the interior of A is contained in B. Homework Equations The interior of A:={a: there exists a neighborhood which is a subset of A} The Attempt at a Solution I can prove that the interior of A is...
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