Vout = Vin (1 + R2/R1) According to this positive feedback topology - made an error here, it's Vout = Vin(-R2/R1) (edit)
Now I read in a tutorial - http://www.electronics-tutorials.ws/systems/feedback-systems.html , that
If the input voltage Vin is positive, the op-amp amplifies this positive signal and the output becomes more positive. Some of this output voltage is returned back to the input by the feedback network.
Thus the input voltage becomes more positive, causing an even larger output voltage and so on. Eventually the output becomes saturated at its positive supply rail.
How does this happen? Shouldn't Vout be constant at a particular value, because we aren't changing Vin or the resisitors right? Shouldn't the equation Vout= Vin ( 1 +r2/r1) always hold? Error Vout = Vin(-R2/R1) (edit)
So how is the Vout increasing iteratively?