48 ***boosting error and weight

#first
n=10
d=1/n
a=0.5*log((1-e)/e)
e=0.3

#for T
dit1=d*exp(-1*a)
#for f
dif1=d*exp(a)
z1=7*dit1+3*dif1
z1

#second
e1=3*dit1/z1
e1
w1=0.5*log((1-e1)/e1)
w1
dit2t=dit1*exp(-1*w1)
dit2f=dif1*exp(-1*w1)
dif2=dit1*exp(w1)
z2=4*dit2t+3*dit2f+3*dif2
z2

#third
e3=3*dit2t/z2
e3
a3=0.5*log((1-e3)/e3)
a3