Projectile motion with non-uniform gravity.

[Thimo]

I am trying to answer a question about projectile motion were the change in height is that significant that the gravity cannot be assumed constant.

 

[Nugatory]

If we don't know what the question is, we're not going to be able to help you with it... But if you're going to post the actual question, chances are the post should go into the homework forums section: https://www.physicsforums.com/forums/introductory-physics-homework.153/

Aside from that, we can give you one big hint: Calculus was invented to take on problems like this one.