Recent content by 6.28318531

  1. 6

    What is the maximum load of an odd shaped beam with a hollow u shaped fitting?

    Sorry about the diagram its meant to be as though you were looking at the I. The u fitting runs the length of the beam, and it as at least as wide as the beam. I wouldn't think it was of negligible size. It isn't intended to apply load to the top of the I beam.
  2. 6

    What is the maximum load of an odd shaped beam with a hollow u shaped fitting?

    Homework Statement This isn't homework, but I thought I would post it here as maybe more people would see it, and as I am not an engineer, it requires someone with more experience. The section is effectively an I beam with a hollow u shaped fitting along the top (see my rough sketch). I just...
  3. 6

    Flux & Circulation Homework: Find Values & Prove Non-Zero Flux

    Ah now I see for the flux part; Look at each quadrant {x,y>0} {x,y<0} {x>0, y<0} and {x<0,y>0} When x, y> 0, The integral evaluates to a value. Let ∫CF.n ds = f Then for x,y<0 the integral becomes ∫F( -P, -Q) .n ds = - f Then for x> 0, y< 0 ∫F(P(x,-y), Q(x,-y)).n ds= a ≠f...
  4. 6

    Flux & Circulation Homework: Find Values & Prove Non-Zero Flux

    Homework Statement Let F(x,y) = ( P(x,y), Q(x,y)) be a vector field that is continuously differentiable along the closed smooth curve C : x2+y2 = 1. Moreover let -F(x,y) = F( -x, -y)≠ 0 and P(x,y) = -P(-x,y) and Q(x,y) = Q(-x,y). Determine all the possible values of the circulation...
  5. 6

    Simple Excel VBA problem; Applying a formula to a column if it contains a number

    Hello, I have a relatively simple problem, You have two columns filled with numbers. I want my macro to go through and check the columns or one of the colums to see if it has a number in it, then operate on those numbers and display an output in a third column . I tried this; Sub...
  6. 6

    Does physics forbid such a device; a heat destroyer

    What about something based on this; ' http://phys.org/news/2011-06-quantum-knowledge-cools-entropy.html
  7. 6

    How to Solve Equations with Integrals Using FTC and Chain Rule?

    @JJacquellin Sorry I should have been a bit clearer, f(s,t) is unknown. We are given g(t) and g(s). So then f is actually f(a,b,s,t), as you said? I think I can see where this is going but would you mind elaborating on how we can use FTC and the chain rule. I am still not 100% sure. Thanks
  8. 6

    How to Solve Equations with Integrals Using FTC and Chain Rule?

    Yeah s and t are independent, but isn't the problem the fact that a and b are constants,and we don't know what f is, and as such the FTC doesn't really get us anywhere useful?
  9. 6

    How to Solve Equations with Integrals Using FTC and Chain Rule?

    Hi, How would one go about solving equations like ∫^{b}_{a}f(s,t)g(s)ds=g(t),for f(s,t). Could we turn it into a differential equation somehow? Thanks
  10. 6

    Simple vector function problem, find slope of tangent?

    Homework Statement Show that the curve r = (t2,t3-t) Intersects itself at (1,0), and find the slopes of the tangents at this point. Homework Equations The Attempt at a Solution Okay I can show it intersects itself there, but what I am having trouble with is when they say slopes...
  11. 6

    Transformations and joint pdf's

    I think I see what you mean so fy(y)= f( g-1(y1,y2)) . Jacobian[ g-1(y1,y2)]
  12. 6

    Homeomorphism from (0,1) to R

    You are close, you just need to change a few things. Also Do you have to use a trig function? What about x/1-x2, that maps (-1,1) -> ℝ, could you modify that?
  13. 6

    Transformations and joint pdf's

    Homework Statement Let X1 and X2 be random variables having a joint pdf, fX1X2(x1,x2). Suppose that Y1=X1X2, and Y2=X1X2 Use the transformation result to derive an expression for the joint pdf of Y1 and Y[SUB]2 in terms of that for X1 and X2 Homework Equations The single random...
  14. 6

    Not a homeomorphism R^n to R^m

    Thanks for taking time to reply, you've all given me some interesting reading.
  15. 6

    Not a homeomorphism R^n to R^m

    Thanks for that. It all looks pretty interesting. Now I see why my lecturer wasn't going to show us the proof.
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