请用MATLAB解下面方程组.[r1,r2,a1,a2,B]=solve('670=(r1+1)*a1+(r2+1)*a2+2*160*cos(B)','sin(B)=(r2-r1)/160','1=r2/r1','a1+a2=2*pi','a1=pi-2*(r2-r1)/160')直接解出来结果是:r1 =0pir2 =pipia1 =pipia2 =-(pi-175)/pi-(pi-495)/piB =-(pi-175)/p
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![请用MATLAB解下面方程组.[r1,r2,a1,a2,B]=solve('670=(r1+1)*a1+(r2+1)*a2+2*160*cos(B)','sin(B)=(r2-r1)/160','1=r2/r1','a1+a2=2*pi','a1=pi-2*(r2-r1)/160')直接解出来结果是:r1 =0pir2 =pipia1 =pipia2 =-(pi-175)/pi-(pi-495)/piB =-(pi-175)/p](/uploads/image/z/11499435-27-5.jpg?t=%E8%AF%B7%E7%94%A8MATLAB%E8%A7%A3%E4%B8%8B%E9%9D%A2%E6%96%B9%E7%A8%8B%E7%BB%84.%5Br1%2Cr2%2Ca1%2Ca2%2CB%5D%3Dsolve%28%27670%3D%28r1%2B1%29%2Aa1%2B%28r2%2B1%29%2Aa2%2B2%2A160%2Acos%28B%29%27%2C%27sin%28B%29%3D%28r2-r1%29%2F160%27%2C%271%3Dr2%2Fr1%27%2C%27a1%2Ba2%3D2%2Api%27%2C%27a1%3Dpi-2%2A%28r2-r1%29%2F160%27%29%E7%9B%B4%E6%8E%A5%E8%A7%A3%E5%87%BA%E6%9D%A5%E7%BB%93%E6%9E%9C%E6%98%AF%EF%BC%9Ar1+%3D0pir2+%3Dpipia1+%3Dpipia2+%3D-%28pi-175%29%2Fpi-%28pi-495%29%2FpiB+%3D-%28pi-175%29%2Fp)
请用MATLAB解下面方程组.[r1,r2,a1,a2,B]=solve('670=(r1+1)*a1+(r2+1)*a2+2*160*cos(B)','sin(B)=(r2-r1)/160','1=r2/r1','a1+a2=2*pi','a1=pi-2*(r2-r1)/160')直接解出来结果是:r1 =0pir2 =pipia1 =pipia2 =-(pi-175)/pi-(pi-495)/piB =-(pi-175)/p
请用MATLAB解下面方程组.
[r1,r2,a1,a2,B]=solve('670=(r1+1)*a1+(r2+1)*a2+2*160*cos(B)','sin(B)=(r2-r1)/160','1=r2/r1','a1+a2=2*pi','a1=pi-2*(r2-r1)/160')
直接解出来结果是:
r1 =
0
pi
r2 =
pi
pi
a1 =
pi
pi
a2 =
-(pi-175)/pi
-(pi-495)/pi
B =
-(pi-175)/pi
-(pi-495)/pi
可是用手算的结果是a1=a2=pi,r1=r2=(175-pi)/pi,B=0
请用MATLAB解下面方程组.[r1,r2,a1,a2,B]=solve('670=(r1+1)*a1+(r2+1)*a2+2*160*cos(B)','sin(B)=(r2-r1)/160','1=r2/r1','a1+a2=2*pi','a1=pi-2*(r2-r1)/160')直接解出来结果是:r1 =0pir2 =pipia1 =pipia2 =-(pi-175)/pi-(pi-495)/piB =-(pi-175)/p
你的计算结果是没有错的.
solve()函数的解是按先字母顺序后数字顺序排列的,字母是先大写后小写.不能手动指定解的顺序.
改成如下形式即可.
[B,a1,a2,r1,r2]=solve('670=(r1+1)*a1+(r2+1)*a2+2*160*cos(B)','sin(B)=(r2-r1)/160','1=r2/r1','a1+a2=2*pi','a1=pi-2*(r2-r1)/160')
[B,a1,a2,r1,r2]也可以写成[B a1 a2 r1 r2],效果是一样的.
另外也想想你请教个问题:
我的6.5版本的MATLAB,运行你这代码提示“未定义变量pi”,我晕!
我的2010a版本倒不会提示“未定义变量pi”,但是计算出的结果全是数值解.
我知道2008a版本开始,其符号计算内核由MAPLE换成了Mupad(Mupad远次于MAPLE,很多积分都无法计算出结果.但是这是Mathworks和MAPLE商业竞争的后果,悲剧的用户.),不知道是不是这个原因,希望你告知你的MATLAB版本.