syms y(x);
dy=diff(y,x);
fun=diff(y,x,2)+3*diff(y,x)+7*y== 5+5*cos(1500*x);
con1=y(0)==0;
con2=dy(0)==3;
conds=[con1 con2];
sol=dsolve(fun, conds)
ssol=simplify(sol)