Matlab求解多元多次方程组
答案:2 悬赏:50
解决时间 2021-01-15 20:04
- 提问者网友:雾里闻花香
- 2021-01-15 07:11
Matlab求解多元多次方程组
最佳答案
- 二级知识专家网友:一袍清酒付
- 2021-01-15 08:16
建议用解非线性方程组的方法求解,fsolve()函数,先设定初值,知道解的大致的范围后,再以此值为初值,在设定的精度下求解。
用matlab解一道复杂的多元非线性方程组;
参考如下:
建立 Myfun.m 文件
function F = myfun(x,a)
E = a(1);
I = a(2);
R0 = a(3);
R1 = a(4);
T = a(5);
A = a(6);
v = a(7);
rho = a(8);
F = [ (T - rho * A * v^2) * sin(x(3)) * x(1) - (T * cos(x(3)) + rho * A * v^2 - rho * A * v^2 * cos(x(3))) * x(2) - E*I/(R0 + R1);
(1/3) * (T - rho * A * v^2) * sin(x(3)) * x(1)^3 - (1/2) * (T * cos(x(3)) + rho * A * v^2 - rho * A * v^2 * cos(x(3))) * x(2) * x(1)^2 - E* I * x(2);
(T - rho * A * v^2) * sin(x(3)) * x(1)^2 - (T * cos(x(3)) + rho * A * v^2 - rho * A * v^2 * cos(x(3))) * x(2) * x(1) - E* I * x(3)];
建立一个执行文件
clc
clear
a = zeros(8);
display('# Pls input the known parameters: #')
a(1) = input('E = ');
a(2) = input('I = ');
a(3) = input('R0 = ');
a(4) = input('R1 = ');
a(5) = input('T = ');
a(6) = input('A = ');
a(7) = input('v = ');
a(8) = input('rho = ');
display('# Pls input the initial point: #')
x0 = zeros(3);% Make a starting guess at the solution
x0(1) = input('x1 = ');
x0(2) = input('y1 = ');
x0(3) = input('phi = ');
options = optimset('Display','iter'); % Option to display output
[x,fval] = fsolve(@(x) myfun(x,a),x0,options) % Call solver
运行,输入已知的几个参数,再输入初始搜索点,即可。
用matlab解一道复杂的多元非线性方程组;
参考如下:
建立 Myfun.m 文件
function F = myfun(x,a)
E = a(1);
I = a(2);
R0 = a(3);
R1 = a(4);
T = a(5);
A = a(6);
v = a(7);
rho = a(8);
F = [ (T - rho * A * v^2) * sin(x(3)) * x(1) - (T * cos(x(3)) + rho * A * v^2 - rho * A * v^2 * cos(x(3))) * x(2) - E*I/(R0 + R1);
(1/3) * (T - rho * A * v^2) * sin(x(3)) * x(1)^3 - (1/2) * (T * cos(x(3)) + rho * A * v^2 - rho * A * v^2 * cos(x(3))) * x(2) * x(1)^2 - E* I * x(2);
(T - rho * A * v^2) * sin(x(3)) * x(1)^2 - (T * cos(x(3)) + rho * A * v^2 - rho * A * v^2 * cos(x(3))) * x(2) * x(1) - E* I * x(3)];
建立一个执行文件
clc
clear
a = zeros(8);
display('# Pls input the known parameters: #')
a(1) = input('E = ');
a(2) = input('I = ');
a(3) = input('R0 = ');
a(4) = input('R1 = ');
a(5) = input('T = ');
a(6) = input('A = ');
a(7) = input('v = ');
a(8) = input('rho = ');
display('# Pls input the initial point: #')
x0 = zeros(3);% Make a starting guess at the solution
x0(1) = input('x1 = ');
x0(2) = input('y1 = ');
x0(3) = input('phi = ');
options = optimset('Display','iter'); % Option to display output
[x,fval] = fsolve(@(x) myfun(x,a),x0,options) % Call solver
运行,输入已知的几个参数,再输入初始搜索点,即可。
全部回答
- 1楼网友:不如潦草
- 2021-01-15 08:41
一般是因为方程不收敛导致的
你试一下数值解法
你试一下数值解法
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