6.15 A BJT differential amplifier is biased from a 2-mA constant-current source and includes a 100-resistor in each emitter. The collectors are connected to Vcc via 5-k resistors. A differen- tial input signal of 0.1 V is applied between the two bases. (a) Find the signal current in the emitters (i.) and the signal voltage be for each BJT. (b) What is the total emitter current in each BJT? (c) What is the signal voltage at each collector? Assume a = 1. (d) What is the voltage gain realized when the output is taken between the two collectors?