时间戳

首页 > 解决方案 > Matlab“求解”没有给出方程的两个根

matlab - Matlab“求解”没有给出方程的两个根

问题描述

我正在尝试求解等熵流的马赫数面积方程。这个方程有两个真正的正根，但是当我试图用“求解”例程求解时，我无法得到其中的任何一个。

解方程的代码：

gamma = 1.4;
L     = 3;
n     = 30;

dx = L/n;
x  = 0;
for i=1:n+1
A(i)  = 1 + 2.2*( x - 1.5 )^2;
X(i)  = x;
x     = x + dx;
end
A0 = min(A);

for i=1:1 %n1
syms M    
eqn  = (A(i)/A0)^2 == ( 1/M^2 )*( ( 2/(gamma+1) )*( 1+0.5*(gamma-1)*M^2 ) )^( (gamma+1)/(gamma-1) )
solM = solve(eqn,M)
% Mach_is(i) = solM;
end

我注释掉循环遍历整个向量，因为它崩溃了我得到的输出：

  (1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 1))^(1/2)
  (1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 2))^(1/2)
  (1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 3))^(1/2)
  (1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 4))^(1/2)
  (1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 5))^(1/2)
  (1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 6))^(1/2)
 -(1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 1))^(1/2)
 -(1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 2))^(1/2)
 -(1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 3))^(1/2)
 -(1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 4))^(1/2)
 -(1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 5))^(1/2)
 -(1/root(z^6 - (40824726*z^5)/390625 + (3*z^4)/5 + (4*z^3)/25 + (3*z^2)/125 + (6*z)/3125 + 1/15625, z, 6))^(1/2)

谁能建议我为什么会得到这个以及如何求解方程？

标签： matlabareaequation-solvingmach

解决方案

推荐阅读