April 24th, 2013, 10:31 am
QuoteOriginally posted by: edouardI'm sorry, this is basic, and you're probably going to laugh, but this is something that puzzles me.I'm expecting ln(x/y)=ln(x)−ln(y) [something like the (natural) logarithm quotient rule, see Laws of Logarithms]But when doing some trials with Excel, I can't get such an equality. There is always a slight difference between ln(x/y) and ln(x)−ln(y).??Example of results in Excel:ln(3200/2345) = 0.310865407907438000000ln(3200) - ln(2345) = 0.310865407907439000000Ouch! And, I also get such unexpect results with R> options(digits = 22)> log(3200/2345)[1] 0.3108654079074381737513> log(3200) - log(2345)[1] 0.3108654079074391063386> log(3200/2345) == log(3200) - log(2345)[1] FALSE
Last edited by
tags on April 23rd, 2013, 10:00 pm, edited 1 time in total.