题目内容
(1)计算:(
)6-
×(
)
-(-2013)0
(2)已知log73=a,log74=b,用a,b表示log4948.
| 3 | 2 |
| 7 |
| 5 |
| 25 |
| 49 |
| 1 |
| 2 |
(2)已知log73=a,log74=b,用a,b表示log4948.
(1)(
)6-
×(
)
-(-2013)0
=2
-
×
-1
=2-1-1
=0.
(2)∵log73=a,log74=b,
∴log4948=
log7(3×16)
=
(log73+log716)
=
(log73+2log74)
=
(a+2b).
| 3 | 2 |
| 7 |
| 5 |
| 25 |
| 49 |
| 1 |
| 2 |
=2
| 6 |
| 3 |
| 7 |
| 5 |
| 5 |
| 7 |
=2-1-1
=0.
(2)∵log73=a,log74=b,
∴log4948=
| 1 |
| 2 |
=
| 1 |
| 2 |
=
| 1 |
| 2 |
=
| 1 |
| 2 |
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