LOGA F X( )>G X( )⇔ F X( )>AG X( )(A>1) < ≠ ≤ → ∀ ∈0 1, 0 (*)(1) A B DUNG X R> → < < > → ⇔ <( ) ( ) ( ) ( )LOGA F X( )>G X( )⇔ F X( )<AG X( ) (0< <A 1)F XA B A B F X B* 0 1, 0 * LOGA > > → ⇔ >(2) ( ) (...
2. Phương pháp giải:
(1) Dạng 1:
log
a
f x
( )
>
g x
( )
⇔
f x
( )
>
a
g x
( )
(
a
>
1)
< ≠
≤ →
∀ ∈
0
1,
0
(*)
(1)
a
b
dung x R
>
→ < <
> →
⇔
<
( )
( )
( )
( )
log
a
f x
( )
>
g x
( )
⇔
f x
( )
<
a
g x
( )
(0
< <
a
1)
f x
a
b
a
b
f x
b
*
0
1,
0
*
log
a
> > → ⇔
>
(2)
( )
( )