[交流] 【求助】解方程组的错误 已有5人参与

Originally posted by luohubin at 2010-07-29 14:54:19:
大家好，我刚接触matlab，想求两条曲线的公切线方程，写了代码如下
function s=comtan(p)
syms x1 x2;
a=p(1);
b=p(2);
c=p(3);
d=p(4);
e=p(5);
g=p(6);
h=p(7);
i=p(8);
j=p(9);
k=p(10);
f1=a+b* ...

% 求两个半圆的公切线
clc;clear all;close all
syms x
y1=sqrt(1-x.^2);
y2=2-sqrt(1-x.^2);
% 求导
y11=diff(y1,x);
y22=diff(y2,x);
% 求切线斜率 k0 及切点坐标（x0，y0）
f1=y2-y1;
f2=y22-y11;
x0=solve(f1);
k0=solve(f2);
y0=subs(y1,x0);
y=k0*x+y0; % 切线方程
x1=-1:0.001:1; % 定义自变量
y=subs(y,x1,'r'); % 切线
y1=subs(y1,x1); % 半圆 1
y2=subs(y2,x1); % 半圆 2
% 绘图
plot(x1,y)
hold on
plot(x1,y1)
plot(x1,y2)
axis([-1 1 0 2])

Originally posted by luohubin at 2010-08-04 09:11:58:

版主，还是有问题啊，我是 R2010版本，看你说的做了，下面是出来的信息
Warning: Explicit solution could not be found.
> In solve at 81
  In comtan at 19

s =

[ empty sym ]


ans =
...