1. The problem statement, all variables and given/known data Find the series expansion of ln(x + sqrt(1+x2)) 2. Relevant equations ln(1+x) = x - x2 /2 + x3/3 - x4/4 + ... 3. The attempt at a solution I don't know how to solve this. If it was ln(1+f(x) ) I know I could substitute the x's for f(x) in the ln(1+x) series expansion, but I don't know what to do since the ln isn't in the correct form. Am I supposed to rederive the series from scratch?