Question

用matlab 中solve求解线性方程组，求大神帮帮，谢谢啦。。。

syms s3,x3,x4,se;
[s3,x3,x4,se]=solve('s3*cos(x3)=0.125*cos(0.174)','s3*sin(x3)=0.275+0.125*sin(0.174)','0.6*cos(x3)+0.15*cos(x4)-se=0','0.6*sin(x3)+0.15*sin(x4)=0.3')
结果出现：
s3 =

z2
z2

x3 =

(3*cos(z3))/5 + (3*cos(z4))/20
(3*cos(z3))/5 + (3*cos(z4))/20

x4 =

z3
z3

se =

z4
为何呢？应该为数字吧。。。

Answer 1

按你的语句 运行完的结果和你说的不一样：
s3 =

-.32117320644214174679478487023195
.32117320644214174679478487023195

x3 =

-.22999275816638841028516780789997+.15000000000000000000000000000000*(-3.-16.*sin(x3)^2+16.*sin(x3))^(1/2)
.22999275816638841028516780789997+.15000000000000000000000000000000*(-3.-16.*sin(x3)^2+16.*sin(x3))^(1/2)

x4 =

-1.9641858908552267692932569383891
1.1774067627345664691693864448904

se =

-1.*asin(4.*sin(x3)-2.)
-1.*asin(4.*sin(x3)-2.)

第一条语句写不写都无所谓吧，本来用solve解出来的就是符号解，就不需要再把s3,x3,x4,se定义成符号，而且syms s3,x3,x4,se;的逗号应该换成空格。

Answer 2

三角函数属于非线性

非线性用fsolve函数