נתון log5 = 0.7 , log3 = 0.5 חשב את log0.45 ואת log18
תודה רבה לעוזרים
log0.45 = log45/100 = log45 - log100 = log5*9 - 2 = log5 + log9 - 2 = log5+log3^2 - 2 = log5+2log3-2=0.7+2*0.5-2 = 0.7+1-2=-0.3
log 18 = log (9*2) = log 3^2 + log 2 = 2log 3 + log 2נטפל בלוג 2log 2 = log (10/5) = log 10 - log 5 = 1 - log 5-->log 18 = 2 * 0.5 + (1 - log 5) = 1 + 1 - 0.7 = 1.3