
ReW
T
=
1=
T
NW
and for the case of the three assets in an analytic form:
BCCBACCAABBA
CC
BBAA
w
swwswwswwswswswmin
222
222222
+++++
s.t.
R)r(Ew)r(Ew)r(Ew
CCBBAA
=++
1=++
CBA
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Note: If we do not use the first constraint and in the absence of a risk-free
rate we will get the minimum variance portfolio. It is actually advisable to
first get the minimum variance portfolio before we proceed in a real problem.
Then, by changing the level of desire return, we trace points on the efficient
frontier.
To solve this problem, we make two simplifications to the problem. First we
replace everywhere
C
w with
ww −−1 . Second, we rearrange the
constraint:
R)r(Ew)r(Ew)r(Ew
CCBBAA
=++
to
0=++− )r(Ew)r(Ew)r(EwR
CCBBAA
and since it equals zero, we multiply it with a constant ? and we get:
0=++− ))r(Ew)r(Ew)r(EwR(?
CCBBAA
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