Error using trustnleqn (line 28)

Hello everyone,

I'm trying to solve non linear equations system using fsolve. I'm beginner in matlab I just have no idea what's going on with my program when I tried to run it, there's an error message in the command window:

function F = BEB(x)

n = 50; %number of stations


F(1) = x(1) - (2) / (1-x(2))*((1+x(2))+ 16*(1+2*x(2))+ ((x(2)^3)/(1-2*x(2)))*((x(2)/1-x(2))-((x(2)/1-x(2))^6)/((x(2)/1-x(2))^2))*((64*x(2)^3)/1-3*x(2))*(2*(x(2)/1-x(2))-((2*(x(2)/1-x(2)))^6))/(2*(x(2)/1-x(2))^2)); 

F(2) = (1-x(1))^n + x(2) -1;

i run it:

fun = @BEB
x0 = [0 0]
x = fsolve (fun, x0)

Answer 1

[Walter Roberson]

Part of your expression is

((x(2)/1-x(2))^6)/((x(2)/1-x(2))^2))

The right hand side of that is (x(2)/1 - x(2))^2 which is (x(2) - x(2))^2 which is 0^0 which is 0. You are dividing by that zero. Division by 0 is going to get you one of -inf, +inf, or nan, depending what the numerator works out as. Your numerator happens to work out as 0 because it also has the X(2)/1-x(2) basic unit.

Therefore your expression always includes 0 / 0 which is NaN, so BEB always returns NaN as the first value. Most routines will give up when they see a nan result.

[Amirul Hezry]

so any part that i need to change ? any suggestion

[Walter Roberson]

Post your equations in latex format or a picture of the mathematical form.

[Amirul Hezry]

Assume X(1) = tau (packet transmission probability X(2) = P (probability of collision

[Amirul Hezry]