// Exa 4.19
format('v',5)
clc;
clear;
close;
format('v',9)
// Given data
alpha_dc = 0.99;
I_C = 6;// in mA
I_C= I_C*10^-3;// in A
I_CBO = 15;// in µA
I_CBO= I_CBO*10^-6;// in A
// The emitter current,
I_E = (I_C - I_CBO)/alpha_dc;// in A
// The base current,
I_B = I_E - I_C;// in A 
I_B= I_B*10^6;// in µA
I_B= round(I_B)
disp(I_B,"The value of I_B in µA is");