Exercise 6.6 Feedback wrapped around an NPN - limiting factors

In the circuit below, the opamp is ideal (rin ,rout = 0,aV ). For the BJT, you may assume that iC = IC0 e

q vBEkT, with a finite βfe.

pict

a)
Draw a large signal graph of vOUT as a function of vIN.
b)
Describe the range of vOUT for which the specified BJT element equation(s) hold.
c)
What happens to vX for values of vIN very close to ground?