1. The problem statement, all variables and given/known data Hello, I'm in the middle of a question and I need to expand 1/(x√(1-2cosθ/x)) in powers 1/x up to order of 1/x^3 2. Relevant equations 3. The attempt at a solution This is my attempt to the more complicated question. To get to the final answer, I need to know how to expand the above question. I've simplified to 1/(x√(1-2cosθ/x)). now... do I use taylor expansion? But I'm not give Ao or Xo thus I can't have (X-Xo) Please! Any help would be really appreciated!! Thank you.