问题
解答题
(1)计算:(
(2)已知log73=a,log74=b,用a,b表示log4948. |
答案
(1)(
)6-3 2
×(7 5
)25 49
-(-2013)01 2
=2
-6 3
×7 5
-15 7
=2-1-1
=0.
(2)∵log73=a,log74=b,
∴log4948=
log7(3×16)1 2
=
(log73+log716)1 2
=
(log73+2log74)1 2
=
(a+2b).1 2