我写了个matlab程序，机械原理课的，谁能帮我看看哪错了？

应该怎么改？我也不是很懂，最好详细点，谢谢，是个四杆机构

l1 = 450; l2 = 120; l3 = 400; l4 = 280;
omega2=60;
hd=pi./180;du=180./pi;
n1=1:36:360;
theta2=(n1-1).*hd;
l5 = sqrt(l2.^2 + l1.^2 - 2.*l2.*l1.*cos(theta2));
phi2 = arcsin((l2.*sin(theta2))./l5);
phi3 = arccos((l5.^2 + l4.^2 - l3.^2)./2.*l5.*l4);
theta4 = pi - alpha2 - alpha3;
theta3 = arcsin((l4.*sintheta4 - l2.*sintheta2)./l3);
omega3=(l2.*sin(theta2).*omega2)./(-l3.*sin(theta3));
omega4=(-l2.*cos(theta2).*omega2)./(l3.*cos(theta3));
alpha3=(omega2.*omega2.*l2.*cos(theta2)+omega3.*omega3.*l3.*cos(theta3))./(-l3.*sin(theta3));
alpha4=(omega3.*omega4.*l3.*sin(theta3)+omega2.*omega2.*l2.*sin(theta2))./(l3.*cos(theta3));
subplot(2,2,1);
plot(n1,phi2.*du,n1.phi3.*du) %位置角
subplot(2,2,2);
plot(n1,omega3,n1,omega4) %角速度
subplot(2,2,3);
plot(n1,alpha3,n1,alpha4) %角加速度

arcsin应为asin
arccos应为acos
alpha2和alpha3未定义
sintheta4应为sin(theta4)
sintheta2应为sin(theta2)
n1.phi3.*du应为n1,phi3.*du