Question

value of g at altitude of 1,000,000m is

Answer 1

g=GM/R^2 I believe.
Where G is the gravitational constant
M is the mass of the earth (assuming you want the value of g at 1*10^6m is relative to earth)
R is the radius of the earth, add the height you want to find g at.
I think this is the correct way to do this, let me know if it works :D

Answer 2

For the variation in the value of g with height h, useIf\[h<<R\]then you can simplify using the binomial theorem to obtain