solve('XFDY= -xg1.*sin(wa1)+yg1.*cos(wa1)',' YFDY=xg1.*cos(wa1)+yg1.*sin(wa1)',' XFDY= 50.55*cos(u)','YFDY=50.55*sin(u)',u);
在上式中u为参数变量，wa1等于一个值，XFDY,YFDY为变量，xg1,yg1为关于u的变量，之前有公式表达。但出现以下错误：
错误使用 solve>processString (line 365)
' XFDY= -xg1.*sin(wa1)+yg1.*cos(wa1) ' is not a valid expression or equation.
出错 solve>getEqns (line 286)
eqns = processString(eqns, v, vc);
出错 solve (line 160)
[eqns,vars,options] = getEqns(varargin{:});
出错 solvefenduyuan (line 142)
solve('XFDY= -xg1.*sin(wa1)+yg1.*cos(wa1)',' YFDY=xg1.*cos(wa1)+yg1.*sin(wa1)',' XFDY= 50.55*cos(u)','YFDY=50.55*sin(u)',u);
