clc, clear all
b0=6;
felet=10000;
while abs(felet)>1e-5
    f=12*exp(-b0)-b0*exp(-b0)+b0-6;
    fp=-12*exp(-b0)-(-b0*exp(-b0)+exp(-b0))+1;
    felet=f/fp;
    b0=b0-felet
end
a0=12-b0