Turn on thread page Beta
    • Thread Starter
    Offline

    0
    ReputationRep:
    Find radius of curvature of y=k.arctan(x/k)

    I keep on getting p=25kroot(41)/80, which is wrong...

    Anyone out there?
    Offline

    2
    ReputationRep:
    I get a fairly complex result for rho. What's the value of x for that result of yours?

    I have p=[1+(1+x^2/k^2)^2]^(3/2).k^2(1+x^2/k^2)^2/(-2x)
    • Thread Starter
    Offline

    0
    ReputationRep:
    .25? i'm ok now. I only checked back to say I think I'm ok... but you had already written your thing down. cheers anyway man. I forgot that you raise the top bit to 3/2 and not 1/2. it's that time of the day when I should be asleep... lol
    Offline

    13
    ReputationRep:
    (Original post by Yannis)
    Find radius of curvature of y=k.arctan(x/k)

    I keep on getting p=25kroot(41)/80, which is wrong...

    Anyone out there?
    p = [(1+(dy/dx)²)^3/2]/[d²y/dx²]

    dy/dx = k/(k²+x²)

    d²y/dx² = -2xk/(k²+x²)²

    p = [(1+k²/(k²+x²)²)^3/2]/[-2kx/(k²+x²)]

    = [[(k²+x²)²+k²]/(k²+x²)²]^3/2].(x²+k²)/(-2kx)

    dot dot dot

    it's pretty tedius algebra from there
    • Thread Starter
    Offline

    0
    ReputationRep:
    cheers man... I suppose you were working on it before I got to post my last one. Thanks a bunch anyway. At least I know there are some people around if I need help. I'm pretty sure I've sorted it now. I just forgot the power of [1 + (dy/dx)^2] bit. too late.
 
 
 
Poll
Do you think parents should charge rent?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.