Finding deboos Integrator time constant and transfer function

I tried to determine the transfer function and time constant of deboo's non-inverting integrator. If I calculate with an ideal OP-AMP, then my calculation fails if the ratio of R2/R1 and R4/R3 is the same (zero in the denominator). Did I miscalculate something? Algebra is not my friend. What could be the problem?

You can see my calculations below:

EDIT:

I calculated not neglecting Aol. The time constant looks good, but the K doesn't. What could be the problem?