Recent content by Mr Davis 97

  1. Mr Davis 97

    Dimension of set of all linear maps that map three elements to zero

    Sorry, ##a = \operatorname{dim} V## and ##b = \operatorname{dim} W##. And yeah, I actually did that and I think I was able to solve it in that case. Basically, if we're trying to find the dimension of ##\{ T\in \mathrm{Hom}(V,W) : T(v_1) = 0 \}##, where ##v_1## is nonzero, then if we define...
  2. Mr Davis 97

    Help with picking out which point has the most negative derivative

    But I guess what I'm saying is that wouldn't this problem restrict itself to the interval ##[0.5, 5]## because that's all we're given?
  3. Mr Davis 97

    Help with picking out which point has the most negative derivative

    All we're given is that y = f(x). We don't know what kind of function it is. And it probably isn't ##-\infty## because that seems too complex for the nature of the question.
  4. Mr Davis 97

    Algebra word problem about planning a concert

    This seems like a simple problem, but I am a little confused by a few things. For one, what is the use of the piece of information that when they charged $100 per person they got 3000 people to come? Also, how should I proceed with the information "for every $2 decrease in price they would have...
  5. Mr Davis 97

    I Trying to understand terms in a problem

    Any hints? I feel for someones who knows topology this would be an easy problem
  6. Mr Davis 97

    Sum of sides of n polygons in quadrilateral is no more than 4n

    A line in this case is a segment from one side of the quadrilateral to the other. Here is the problem I am actually trying to solve: Let ##Q## be a convex quadrilateral which is cut into convex pieces (cells) by a finite number of lines. For any collection ##(Q_i)_1^n## of these cells...
  7. Mr Davis 97

    Sum of sides of n polygons in quadrilateral is no more than 4n

    I can construct examples that are less than or equal to ##4n## quite easily, but for the life of me I cannot come with example where it's greater than
  8. Mr Davis 97

    I Trying to understand terms in a problem

    A convex disc is any compact, convex set with non-empty interior
  9. Mr Davis 97

    I Trying to understand terms in a problem

    So as someone who has a limited understanding of topology, what would be a hint or a first step for this?
  10. Mr Davis 97

    I Trying to understand terms in a problem

    Here is the problem: Let ##C## be a convex disc in the plane, and ##C_1## and ##C_2## be two translates of ##C##. Prove that ##C_1## and ##C_2## are non-crossing, that is, it isn't possible that both ##C_1 - C_2## and ##C_2 - C_1## are non-connected. Here is my question: What exactly do the...
  11. Mr Davis 97

    I How Does Scaling Affect the Coordinates of a Rectangle in the Plane?

    This is a pretty simple question, I am just trying to clear up confusion. Let ##D## be the rectangle in the plane with vertices ##(-1,0),(-1,1),(1,1),(1,0)##. Let ##\lambda >0##. Then what exactly does the set ##\lambda D## look like? Is it correct to say that, for example, ##2D## is the...
  12. Mr Davis 97

    I Why do I get two different values for an integral?

    Suppose ##t \ge 0##. Let ##\displaystyle I(t) = \int_{-\infty}^{\infty}\frac{x \sin (tx)}{x^2+1}~\text{dx}##. Call this form 1. Note that we can also write the integral as $$ \begin{align*} I(t) &= \int_{-\infty}^{\infty}\frac{x \sin (tx)}{x^2+1}~\text{dx} \\ &=...
  13. Mr Davis 97

    I What are the properties of a plane cut into regions by a set of lines?

    Problem: Let ##L## be a set of ##n## lines in the plane in general position, that is, no three of them containing the same point. The lines of ##L## cut the plane into ##k## regions. Prove by induction on ##n## that this subdivision of the plane has ##\binom{n}{2}## vertices, ##n^2## edges, and...
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