applied

2- Solve the following equations: 1) tc=Dx22c, with the B.C.C(0,t)=0,C(L,t)=CA0,C(x,0)=CA0. II) y+4y+3=0y(0)=3,y(0)=1. III) Find the general solution of : x2y4xy+4y=x4+x2