I assume there are some plus signs that aren't rendering for some reason, so that the plane should be
.
You're minimizing
subject to the constraint
. Note that
and
attain their extrema at the same values of
, so we'll be working with the squared distance to avoid working out some slightly more complicated partial derivatives later.
The Lagrangian is
Take your partial derivatives and set them equal to 0:
Adding the first three equations together yields
and plugging this into the first three equations, you find a critical point at
.
The squared distance is then
, which means the shortest distance must be
.
This is s fraction but it can be reduced to 10/11
Simply plug g and h into the equation:
g + h =
(-7) + (3) = -4
The answer would be:
-7sqrt(6x)/4x^3