Hi, I am working through GR by myself and decided to derive the Friedmann equations from the RW metric w. ( +,-,-,-) signature. I succeeded except that I get right value but the opposite sign for each of the Ricci tensor components and the Ricci scalar e.g. For R00 I get +3R../R not -3R../R . I calmly ignored the wrong signs and substituted the opposite sign into the Einstein equations because 1. they worked and 2. it matched the values for G00 G11 given in textbooks. Obviously I am curious as to what I did wrong! Any ideas?? Thanks !!