Jawabanmu

2014-08-26T20:22:47+07:00
A) log 18 = log(3² * 2) = log 3² + log 2 = 2 * log 3 + log 2 = 2(0,4771) + (0,3010) = 1.2552 
b. log 21 = log(7 * 3) = log 7 + log 3 = 0,8451 + 0,4771 = 1.3222 
c. log 10,5 = log(105/10) = log(3 * 5 * 7) / 10) = log 3 + log 5 + log 7 - log 10 = 0,3010 + 0,4771 + 0,8451 - 1 = 0.6232 
d. log (1/7) = log 7^-1 = -log 7 = -0,8451