Problems with functions plot

Hi, I have this functions: TT=0:0.005:15*To;

 Ar=(TT<To).*(alfa*fi*Ao*((1+(TT/To)*(beta-1))))+((TT>=To)&(TT<=Tas)).*(alfa*fi*beta*Ao)+(TT>Tas).*(alfa*fi*beta*Ao*(TT/Tas).^-pp);

 Ad=((TT>=0)&(TT<Tmas)).*((alfa*fi*Ao*(1+(TT/Tmas)*(beta-1)))/(1+(R-1)*(TT/Tmas).^cc))+((TT>=Tmas)&(TT<=Tas)).*(alfa*fi*beta*Ao/R)+(TT>Tas).*((alfa*fi*beta*Ao/R)*(TT/Tas).^-pp);

Both of them should start at the same point with a curve, however the second function 'Ad', has a problem and it draws a straight line instead of the curve it should be, I already checked the equation and it's ok, but I don't know if there is any other problem with variables that I don't know about.

[Youssef Khmou]

hi Virginia,

i can not verify because i need to know the constants To,Tmas,alpha, fi,cc,Ao,beta,R and pp .