log_3(18)=log_3(3^2xx2)log3(18)=log3(32×2)
Use the rule: log_a(bc)=log_a(b)+log_a(c)loga(bc)=loga(b)+loga(c)
=>log_3(3^2)+log_3(2)⇒log3(32)+log3(2)
Use the rule: log_a(a^b)=bloga(ab)=b
=>2+log_3(2)⇒2+log3(2)
This is a simplified answer. However, if you want your answer in decimal form, use a calculator. Since many calculators don't have the capability of finding logarithms with a specific base, use the change of base formula.
log_a(b)=(log_c(b))/(log_c(a))loga(b)=logc(b)logc(a)
Thus, since the lnln button is on most calculators (or just the loglog button),
log_3(2)=ln(2)/ln(3)=log(2)/log(3)approx0.6309log3(2)=ln(2)ln(3)=log(2)log(3)≈0.6309
Thus,
log_3(18)=2+log_3(2)approx2.6309log3(18)=2+log3(2)≈2.6309