Solution of basic inequality: [min((a+1)*(b+2))]Invalid quadratic form(s): not a square

Nonconvex
1 
cvx_begin;
    variable a;
    variable b;
    minimize((a+1)*(b+2));
    subject to
        a>0;
        b>0;
        a*b-a-2*b-2==0;
cvx_end;
#########################
The error is:
错误使用  .*  (line 262)
Disciplined convex programming error:
    Invalid quadratic form(s): not a square.
出错  *  (line 36)
    z = feval( oper, x, y );
出错 Test_cvx2 (line 6)
    minimize((a+1)*(b+2))

#########################
Do the math by hand: min((a+1)*(b+2))=25, when a==4,b==3
Please help me

3

The objective and last constraint are both non-convex. The solution you mention is indeed correct, but is outside of CVX’s scope.