Empty sym: 0-by-1

4 visualizzazioni (ultimi 30 giorni)
ali kaptanoglu
ali kaptanoglu il 7 Set 2020
clc;
clear;
syms x y z
a=-53.774+70+((30*(2*(37.839-x)-y))/((2*z-x)-y));
b=-54.827+70+((30*(2*(38.886-x)-y))/((2*z-x)-y));
c=-55.879+70+((30*(2*(39.932-x)-y))/((2*z-x)-y));
denklem=solve(a,b,c);
denklem.x

Risposte (1)

Walter Roberson
Walter Roberson il 9 Set 2020
Your equations are inconsistent. There is no solution.
>> subs(c,solve([a,b],[x,y]))
ans =
-1/174500 == 0
Your third equation is not consistent with the first two.
  1 Commento
Walter Roberson
Walter Roberson il 9 Set 2020
The problem is in floating point round off.
syms x y z
T = sym(19501769)/sym(349000)
a=-53.774+70+((30*(2*(37.839-x)-y))/((2*z-x)-y));
b=-54.827+70+((30*(2*(38.886-x)-y))/((2*z-x)-y));
c=-T+70+((30*(2*(39.932-x)-y))/((2*z-x)-y));
subs(c,solve([a,b],[x,y]))
The result will be 0.
If you solve([a,b,c]) then you will get a numeric x and y, and z would be 0. This is not the full story. What the above tells you is that with that set of equations, you only have two independent variables, and the third equation will be satisfied if you know the values for any two of the variables.

Accedi per commentare.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by