function y=myfun(x)
 %注意:直接求解非線性方程組
%clear;x1=0.3469;x2=0.1553;x3=2.3762;x4=1.0711;%本行用于調試程序用.
x1=x(1);x2=x(2);x3=x(3);x4=x(4);
seta(1,1)=60;seta(1,2)=130;seta(1,3)=200;seta(1,4)=280;  
fai(1,1)=17;fai(1,2)=44; fai(1,3)=61; fai(1,4)=50;
 for j=1:4
     seta(1,j)=seta(1,j).*pi/180;
     fai(1,j)=fai(1,j).*pi/180;
 end
for j=1:4
   P1(j,1)=1-cos(seta(1,j)-fai(1,j));
   P2(j,1)=sin(fai(1,j)-seta(1,j));
   P3(j,1)=sin(seta(1,j)-fai(1,j));
   P4(j,1)=1-cos(seta(1,j)-fai(1,j));
   P5(j,1)=cos(seta(1,j)-fai(1,j))-cos(seta(1,j));
   P6(j,1)=sin(fai(1,j)-seta(1,j))+sin(seta(1,j));
   P7(j,1)=cos(fai(1,j))-1;
   P8(j,1)=-sin(fai(1,j));
   P9(j,1)=1-cos(fai(1,j));
   f(j,1)=P1(j,1).*x1.*x3+P2(j,1).*x1.*x4+P3(j,1).*x2.*x3+P4(j,1).*x2.*x4+P5(j,1).*x1+P6(j,1).*x2+P7(j,1).*x3+P8(j,1).*x4+P9(j,1);
end
y=f;