Problem 7 - Secant Method... Boundary Value Problem
d(CA)/d(z)=y
d(y)/d(z)=k*CA/DAB
d(CA1)/d(z)=y1
d(y1)/d(z)=k*CA1/DAB
k=0.001
DAB=1.2E-9
err=y-0
err1=y1-0
y0=-130
L=.001
delta=0.0001
CAanal=0.2*cosh(L*(k/DAB)^.5*(1-z/L))/(cosh(L*(k/DAB)^.5))
derr=(err1-err)/(delta*y0)
ynew=y0-err/derr
z(0)=0
CA(0)=0.2
y(0)=-130
CA1(0)=0.2
y1(0)=-130.013
z(f)=0.001