Can you please explain step by step how they got to that answer? If you can add comments to your steps, that way I can understand. Please & thank you.
#6.4 For the BJT differential amplifier of Fig. 6.1 (see below), find the value of the input differential signal, V-V2, that causes i=0.80/Rc1c1c2.
9. (ca): B- = Vn0.25 = -34. cmV
1-1B = 34.6 mV