We prove an OMEGA(loglog(1/epsilon)) lower bound on the depth of any computation tree and any RAM program with operations {+,−,∗,/,leftfloorcdotrightfloor,not,and,or,xor}, unlimited power of answering YES/NO questions, and constants {0,1} that computes sqrtx to accuracy epsilon, for all $x (mo $ [1,2]. Since Newton method achieves such an accuracy in O(loglog(1/epsilon)) depth, our bound is tight.