- #1
smithg86
- 59
- 0
Homework Statement
question: approximate the function f if the ratio R_1 / R_2 is about 1000.
given:
the van der pauw equation for resistivity:
\rho = ( pi * d / ln[2] ) * (R_1 + R_2})/2 * f(R_1 / R_2),
where f is a function of the ratio R_1/R_2 only and satisfies the relation:
(R_1- R_2)/(R_1+R_2) = f arccosh{exp(ln[2]/f) / 2}.
from van der pauw's 1958 paper:if R_1 and R_2 are almost equal, f can be approximated by the formula
f ~ 1 - [ (R_1 - R_2) / (R_1 + R_2) ]^2 * ln[2] / 2 - [(R_1 - R_2)/(R_1 + R_2)]^4 * {(ln[2])^2 / 4 - (ln[2])^3 / 12}.
Homework Equations
-
The Attempt at a Solution
I have no idea how to start this.