对方程25*c^2/64*B^10-15*b*c/16*B^8+(9*b/16-5*c*u/4)*B^6+c*b*u/2*B^4+(u^2+v^2)*B^2-A^2=0用牛顿迭代法求数值解,使用matlab编程
时间: 2023-11-14 21:41:37 浏览: 133
以下是使用matlab实现牛顿迭代法求解方程的代码:
syms B b c u v A
f = 25*c^2/64*B^10 - 15*b*c/16*B^8*(9*b/16-5*c*u/4)*B^6 + c*b*u/2*B^4*(u^2*v^2)*B^2 - A^2;
dfdB = diff(f,B);
dfdb = diff(f,b);
dfdc = diff(f,c);
dfdu = diff(f,u);
dfdv = diff(f,v);
x = [1 1 1 1 1]';
tol = 1e-10;
iter = 0;
maxiter = 100;
while (norm(double(subs(f,[B b c u v A],x))) > tol) && (iter < maxiter)
J = [double(subs(dfdB,[B b c u v A],x)) double(subs(dfdb,[B b c u v A],x)) double(subs(dfdc,[B b c u v A],x)) double(subs(dfdu,[B b c u v A],x)) double(subs(dfdv,[B b c u v A],x))];
delta = -J\double(subs(f,[B b c u v A],x));
x = x + delta;
iter = iter + 1;
end
if iter == maxiter
disp('Maximum number of iterations reached')
else
disp(['Solution: B = ' num2str(x(1)) ', b = ' num2str(x(2)) ', c = ' num2str(x(3)) ', u = ' num2str(x(4)) ', v = ' num2str(x(5))])
end
在这个代码中,我们首先定义了方程和其各个变量的偏导数。然后我们选择了一个初始点x,开始迭代过程。在每一次迭代中,我们计算了方程的雅可比矩阵,求解出delta,然后将x更新为x+delta。迭代过程在达到一定精度或最大迭代次数之前一直进行。最后,我们输出迭代结果,或者提示达到最大迭代次数。
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