n1=260; z1=14; z2=56; L1=175; L2=420; l1=360; l2=111.246; l3=728.115; %输入初始数据
         j1=0:pi/10:2*pi;
         w1=2*pi*n1/60;
         w2=w1*z1/z2;j=(l1+l2*sin(j1))/(l2*cos(j1));
         if j<0    j2=pi+atan(j);
         else     j2=atan(j);  end                           
          S=-(l3*cos(j2));                                    
          s=sqrt(l1*l1+l2*l2+2*l1*l2*sin(j1));        
          wB=l2*w2*cos(j1-j2)/s;                           
           Va=-(l2*w2*sin(j1-j2));
         V=-wB*l3*sin(j2);                                 
         e=-((2*Va*wB+l2*w2*w2*sin(j1-j2))/s);                                             
         a=e*l3*sin(j2)+wB*wB*l3*cos(j2);
plot(j1/pi*180,S,'-',j1/pi*180,V,':',j1/pi*180,a,'-.'),grid
legend('S','V','a')
是用C++程序写的，运行是对的，但在matlab上却画出一条直线怎么回事啊？