Question: artificial ECG signal

j:=500:tp:=0.07*j:Ap:=0.25:Aq:=0.3:tq:=0.03*j:tr1:=0.05*j:Ar:=2:As:=0.4:tr2:=0.04*j:ts:=0.04*j:tt:=0.17*j:At:=0.4:
u1:=0:
u2:=(Ap/2)*(sin((2*Pi*t/tp)+(3*Pi/2))+1);
u3:=0:
u4:=-(Aq/tq)*t:
u5:=(((Ar+ Aq)/tr1)*t)-Aq:
u6:=-(((Ar+ As)/tr2)*t)+Ar:
u7:=((As/ts)*t)- As:
u8:=0:
u9:=(At/2)*(sin((2*Pi*t/tt)+(3*Pi/2))+1):
u10:=0:
     u2 := -0.1250000000 cos(0.1795195802 t) + 0.1250000000

r1:=plot([u1],t=1..0.1*j):
r2:=plot([u2],t=1..tp):
r3:=plot([u3],t=1..0.08*j):
r4:=plot([u4],t=1..tq):
r5:=plot([u5],t=1..tr1):
r6:=plot([u6],t=1..tr2):
r7:=plot([u7],t=1..ts):
r8:=plot([u8],t=1..0.1*j):
r9:=plot([u9],t=1..tt):
r10:=plot([u10],t=1..0.08*j):
with(plots):
display(r1,r2,r3,r4,r5,r6,r7,r8,r9,r10,view=[0..100,-1..3],axes=boxed);

the same above code works in matlab

in maple it isnot