syms rw xw aw b f x r a s ee;
e=-(s*rw*xw-aw*rw*xw-b*ee*f+b*ee*x+b*r*xw+b*ee*r*x-b*ee*r*f+xw+rw*xw-aw*xw+b*xw+s*xw)/(a*x-aw*f+s*x+f-x+b*f-a*f-x*rw+a*rw*x-a*rw*f+rw*f+s*rw*x-aw*rw*f+b*r*f);
>> subs(e,{rw,xw,aw,b,f,x,r,a},{5%,33.3,0.7,1,2.7,37.5,4%,0.77,smps('s','ee')});


??? Error: File: E:\matlab\work\fuzhi.m Line: 4 Column: 1
Missing variable or function.


有高手帮个忙，为什么以上程序总是出错？