Recent content by Knore88

  1. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    When we get to finding y: 20-4\sqrt{x}-y-m=0 20-8-y-m=0 12-y-m=0 y=12-m or do we assume \sqrt{4}=-2?
  2. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    Hey Mark, I was just told "To avoid some confusion in this question, I'll point out that you need to have the constraint in the form "g(x, y) - c" in order to get the correct sign for the Lagrange multiplier. In other words, you need to multiply the constraint, as it's given, by minus one."...
  3. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    Of course. Sorry. In a situation like this would you state -\lambda {x}^{-\frac{2}{3}} > 0 for all x > 0 or do you use the value of x we already found x=4 \therefore -\lambda {x}^{-\frac{2}{3}} = 0.125 > 0 Thank you again
  4. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    Further on this question I need to check the second order conditions. D(x,y,\lambda) = ({f}_{xx}-\lambda {g}_{xx}){({g}_{y})}^{2} - 2({f}_{xy}-\lambda {g}_{xy}){g}_{x}{g}_{y}+({f}_{yy}-\lambda {g}_{yy}){({g}_{x})}^{2} {g}_{y}=-1 {g}_{x}=-2{x}^{-\frac{1}{2}} {g}_{xx}={x}^{-\frac{3}{2}}...
  5. K

    MHB What values of m maximize the utility function for a consumer buying two goods?

    I tried at y = 0 U(\frac{m}{6}, 0 ) ends at {(m-8)}^{2} (So on boundary) Also tried x = 2 U(2, \frac{m-12}{10}) ends at {-95m}^{2}-1536m-6080 both outside of the boundary?
  6. K

    MHB What values of m maximize the utility function for a consumer buying two goods?

    U(x(m), y(m)) = U(\frac{40-m}{24}, \frac{m-8}{8}) = \frac{{m}^{2}+16m+64}{96} Can I choose any point on the constraint? Say y = 10 - 2x x(m) = \frac{100-m}{14} y(m) = \frac{-30-m}{7} U(x(m), y(m)) = \frac{{3m}^{2}+8m-640}{98} Original is larger until a certain point?
  7. K

    MHB What values of m maximize the utility function for a consumer buying two goods?

    A consumer spends a positive amount (m) in order to buy (x) units of one good at the price of 6 per unit, and (y) units of a different good at the price of 10 per unit. The consumer chooses (x) and (y) to maximize the utility function U(x, y) = (x + y)(y + 2). I need to find the optimal...
  8. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    Substituting for m = 70 we have, T = 46 {t}_{1} = 4 {t}_{2} = 42 T(4, 42) = 46 for an m of 70?
  9. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    No problem. T(25, m) = m + 25 (this is larger) But why do we choose this point?
  10. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    Plugging x = 4 into our constraint we get m - 20 - 4\sqrt{4} - y = 0 y = m - 28, and if m = 70, then y = 42?
  11. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    Does it imply that \lambda = -1 and/or x = 4 ?
  12. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    {T}_{x}(x,y) = 1 {T}_{y}(x,y) = 1 {g}_{x}(x,y) = -\frac{2}{\sqrt{x}} {g}_{y}(x,y) = -1 {T}_{x} = \lambda*{g}_{x}: 1 = -\frac{2}{\sqrt{x}}\lambda {T}_{y} = \lambda*{g}_{y}: 1 = -\lambda How does this look?
  13. K

    MHB How Does Changing the Sign of a Constraint Affect Lagrangian Solutions?

    A student wishes to minimize the time required to gain a given expected average grade, 𝑚, in her end-of-semester examinations. Let {t}_{i} be the time spent studying subject i\in{1,2}. Suppose that the expected grade functions are {g}_{1}({t}_{1}) = 40+8\sqrt{{t}_{i}} and {g}_{2}({t}_{2}) =...
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