Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Multivariable sketch

  1. Jan 20, 2006 #1
    Here is the problem i'm having some trouble with. The answer is fairly simple, it is the power of the e function. (the parabola x = y^2 + 1) i'm not sure how to get that, i could use some hints/help, thanks!
  2. jcsd
  3. Jan 20, 2006 #2


    User Avatar
    Homework Helper

    Think about what values for the power of an exponent give a result greater than one.
  4. Jan 21, 2006 #3


    User Avatar
    Science Advisor

    Are you aware that "The answer is fairly simple, it is the power of the e function. (the parabola x = y^2 + 1)" is NOT precisely true? That is, the region you are asked to sketch is NOT the parabola itself. The parabola is a boundary of the region. Indeed if you think about the fact that "power of the e function" is NOT x= y^2+ 1 nor a parabola, you might see what StatusX means!
  5. Jan 21, 2006 #4


    User Avatar
    Homework Helper

    I'll be kind: recall that [tex]e^w \geq 1[/tex] if, and only if, [tex]w\geq 0,[/tex] that is, if, and only if the exponent of e is greater than or equal to 0. You are asked to find (and sketch) all points in xy-plane (e.g. all values of x and y) such that [tex]e^{1-x+y^{2}}\geq 1,[/tex] which occurs if, and only if, [tex]1-x+y^{2}\geq 0[/tex] which describes the region in the xy-plane bounded by (and to the left of) the parabola [tex]x=1+y^{2}[/tex].
  6. Jan 21, 2006 #5
    ohh, i see, i forgot that to get thats how to get the entire function greater than 1, i get it now, thanks everyone!
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook