Tính chất:
loga (a,b >0, a 1)
log 1 0a =
loga a = 1
loga aα = α
loga
a α = α
loga b b = loga b + loga b
1
2
b
= −
÷
loga bα = α loga b
1 logaα b loga b
α
=
logaα bβ β loga b
α
=
log log
log
c a
c
b b
a
=
log loga b b c = loga c
} log log n
n
a b = a b
VD:
4 3 =4 9 =9