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    Maths Question - SIN COS etc

    Have a problem:

    i need to draw a curve using straight equal length lines.

    It has 4 parameters: start X and Y and an end X and Y

    Start X and Y will be the pivot so will never change but i need to work out the end X and Y in order to create a 1/4 circle using equal length lines.

    Any one know of the equation to solve this?

    10 Comments

    Might need to draw what you mean: do you mean you want a set of 4 joined, equal length, straight lines that span from sX:sY to eX:eY that follow are 90 degree arc?

    I think I know what you're asking
    ..effectively what you're trying to do is lay intersecting tangents of equal length on a 1/4 size circle
    correct?
    and what you're trying to achieve is the a formula for the perimeter of the shape formed by the intersecting equi-length tangents
    correct?

    darklight

    I think I know what you're asking..effectively what you're trying to do … I think I know what you're asking..effectively what you're trying to do is lay intersecting tangents of equal length on a 1/4 size circle correct?and what you're trying to achieve is the a formula for the perimeter of the shape formed by the intersecting equi-length tangents correct?



    ......................... Just what I was thinking!.............................................. honest

    Original Poster

    yes!


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    |....................................................................................<------- the curve from the horizontal to the vertical ish lol
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    Edited by: "mds1256" 4th Jan 2011

    snowtiger

    ......................... Just what I was … ......................... Just what I was thinking!.............................................. honest




    ..love things like this...take a look @ this other problem
    link

    hotukdeals.com/mis…e=3

    anyway ...will get back later this afternoon..if you haven't resolved it by then
    cheers
    DL

    Original Poster

    any luck?

    sorry for the late response ...have you made any progress yourself?

    we're looking at a polygonic figure ?
    I assume you know the radius of this 1/4 circle you'd like to draw ?
    so either
    1) we have this circle enclosing a polygon with the tips of the polygon touching the inner perimeter of the circle ( 1/4 circle to be specific )
    or
    2) have the circle just fitting inside the the polygon which would automatically create tangents for you if you see what I mean
    ( rather like fitting a small bicycle wheel into a multisided (angular) hat box so that the wheel touches every angled side( face)
    ..my mums hat boxes come to mind..haha)


    anyway take a look here

    mathopenref.com/pol…tml

    cheers

    Original Poster

    No... still struggling..

    radius is - 6cm

    ..ok will have a go ...be back later..
    cheers

    Original Poster

    worked it out in the end

    var offsetX = 0;
    var offsetY = 100;
    var circleRadius = 600;
    for(i = 0; i<=90; i++)
    {

    x = (Math.cos(i * 3.142 / 180) * circleRadius);
    y = (Math.sin(i * 3.142 / 180) * circleRadius);

    }
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