Solving 2 parameters equation

1 view (last 30 days)
Hamid on 17 Jun 2016
Commented: Hamid on 17 Jun 2016
Hi everyone,
my unknown parameters are D and nR, I want Rg will be less than 0.5
How is it possible?
p=100;
pi=3.14;
asec=0.2179;
k1=1.3663;
Lg=35;
Wg=32;
k2=5.6641;
Lr=3;
b=0.01;
R1=((p/(pi*Lc))*(log((2*Lc)/asec)+((k1*Lc)/sqrt(Lg*Wg))-k2));
R2=((p/(2*pi*nR*Lr))*(log((4*Lr)/b)-1+((2*k1*Lr)/(sqrt(Lg*Wg)))*(((sqrt(nR)- 1))^2)));
Rm= ((p/(pi*Lc))*(log((2*Lc)/Lr)+((k1*Lc)/sqrt(Lg*Wg))-k2+1));
Rg=((R1*R2)-(Rm^2))/((R1+R2)-(2*Rm));
Thank you.

Roger Stafford on 17 Jun 2016
I see no unknown variable ‘D’ here. Also the variable ‘Lc’ is not defined. Do you mean that Lc and nR are actually the two unknowns? Also you need to specifically define ‘Rg’.
This looks as though it calls for ‘fsolve’:
http://www.mathworks.com/help/optim/ug/fsolve.html
Hamid on 17 Jun 2016
Na=(Lg/D)+1;
Nb=(Wg/D)+1;
Lc=(Lg*Nb)+(Wg*Na);
my unknown parameters are D and nR, I want Rg will be less than 0.5.
please write the right code for solving the equation, unfortunately I don't have enough time.
Thanks.