Problem with my mathcad programm (iteration)

[Hs141]

Hello,
I have a problem with a programm that I have made in Mathcad. I don't know enough of Mathcad to solve it.
I have defined the equations in mathcad.
One of these equations has the form: 4/3*Pi(rt^3-r^3 (simplified). I want to know the radius at time t

I have written the following programm:
help(rt,t,r)=o(rt,t,r)-P(rt)
H(rt,t,r,)=O(rt,t,r)-P(rt)-(L*(rt-r0/r0))
V1(rt,t,r)=root(h(rt,t,r),rt)

V2: t--> 1
rt --> r0
W --> W0
rt --> r0
while help(rt,r,t)>0.000000001
t1 --> t+1
r --> r0
W --> W0+4/3*(rt^3-r^3)
V2t-->V1(1.87*10^-5,t1,rt)
V2

at time t+1 then the function rt should be r(t+1) and r --> rt. How can I define that?

Thanks.

 

[IRstuff]

Read the help file on Given-Find. You shouldn't need a program do this, although I can't begin to tell what "this" actually is.

TTFN

FAQ731-376
Chinese prisoner wins Nobel Peace Prize

 

[Hs141]

I need a programm, because I would like to know at every time t the radius. I read the help of given-find, but I think I can't use it in my programm.

I would like to know how I can define in the simplified function!
4/3 * (rt^3-r^3)
After the condition is true, that the new value of rt will be the value of r(t+1) ( which can be found with the root function )and the new value of r will be the value of the last rt. How can I define that?

Thx.