Recent content by Roni1985

  1. R

    Which increases faster e^x or x^e ?

    But you are using the fact: "exponential growth (blank^x) grows faster than x^blank (whatever that is called)" I want to prove it. how do you see that e^x grows faster then ex^(e-1) ?
  2. R

    Which increases faster e^x or x^e ?

    Thanks for the reply. How can you prove it with limits? lim x-> inf and then lim x-> -inf ?
  3. R

    Which increases faster e^x or x^e ?

    Homework Statement which increases faster e^x or x^e ?Homework Equations The Attempt at a Solution My attempt was taking the log of both, assuming it doesn't change anything (is this assumption correct?) x*ln(e) ------------------------ e*ln(x) now I took the derivative 1...
  4. R

    Probability- expected value of Z, where z= X/(1+y)^2

    Well I was thinking that now its uniformly distributed from 1 to 2... isn't it? EDIT: Oh right its still uniform from 0 to 1... omg... I'm so rusty :\ Thanks.
  5. R

    Probability- expected value of Z, where z= X/(1+y)^2

    Hey, thanks for the answer. Is 1+y^2 a typo in your answer? so adding a constant to a uniform r.v. doesn't change it's distribution?
  6. R

    Probability- expected value of Z, where z= X/(1+y)^2

    Homework Statement X & Y are independent r.v.s with uniform distribution between 0 and 1. Z= X/(1+Y)^2 find E[Z]. Homework Equations The Attempt at a Solution Here is what I did. E[Z]= E[X]*E[1/(1+Y)^2] E[X]=1/2 E[1/(1+Y)^2]=? I think that once I know the distribution...
  7. R

    Probability= sum of n uniformly distributed r.v.'s

    I see, I guess the fact that the distribution changes, confused me... Thanks.
  8. R

    Probability= sum of n uniformly distributed r.v.'s

    Homework Statement Xi ~ U(80,120) find the E[X1+X2+...+Xn]=? Homework Equations The Attempt at a Solution Why can't I do this?: E[X1+X2+...+Xn]=n*E[X1] and just find the expected value? Is that because the distribution changes as we increase the number of elements of...
  9. R

    Probability- minimum inventory to satisfy demand

    Ya I'm a lil rusty it's sqrt(20)*20 and the prob is just .95
  10. R

    Probability- minimum inventory to satisfy demand

    oh shoot, that's the variance I guess. so, SD is just 20. But, now I'm thinking maybe I should use the gaussian pdf...? EDIT: I used excel's =NORMINV(0.975,1200,20) And I get 1240 both ways... so I think its good. But if wanted to use the gaussian pdf, how would you calculate it?
  11. R

    Probability- minimum inventory to satisfy demand

    Homework Statement There are 20 customer locations, the demand in each location is normal with mean 60 and SD 20. All 20 locations have independent probabilities. The goal is to cover all of the demand in a month at least 95% of the times. What's the minimum total inventory the company should...
  12. R

    Linear Algebra (Linear Programming) Feasible solutions and extreme points.

    Homework Statement . . . . (c) Find a feasible solution that is not basic. (d) Find a feasible solution that is not an extreme point: justify your answer by using the definition of extreme point. Homework Equations The Attempt at a Solution The whole question is not that...
  13. R

    Basic Topology- when doesn't the reflexive relation hold?

    Oh, I see it now. Thanks very much for the explanation.
  14. R

    Basic Topology- when doesn't the reflexive relation hold?

    When can it not be true? if I understand it correctly, there is always a 1-1 mapping from A to A. Thanks.
  15. R

    Basic Topology- when doesn't the reflexive relation hold?

    lol, I am sorry, I never took topology and the notations are kind of foreign to me. Okay, forget 'R'. '~' = equivalent A is a set and B is a set. I am given a definition, "if there exists a 1-1 mapping of A onto B, A~B". Now, when this is true, the following properties must be satisfied...
Back
Top