高一数学 对数

如题所述

(1)解:原式=lg5x5 + lg2的[3x(2/3)]次方 + lg5lg10x2 + lg2lg2
=lg5+lg5+lg2²+lg5(1+lg2)+lg2lg2
=lg5+lg5+lg2+lg2+lg5+lg5lg2+lg2lg2
=lg5x2+lg5x2+lg2(lg5+lg2)
=2+lg2
(2)解:原式=[log2 5 + log2 (1/5)的1/2次方][log5 2 + log5 (1/2)的1/2次方]
=[log2 5x(根号5 / 5)][log5 2x(根号2 / 2)]
=log2 根号5 log5 根号2
=log2 根号5 log根号5 2(换底公式上下约分)
=1
(3)解:原式=(log2 3的1/2次方 + log2 3的1/3次方)(log3 2 + log3 2的1/2次方)
=(log2 3的5/6次方)(log3 2的3/2次方)
=(5/6)log2 3 x (3/2)log3 2
=5/6 x 3/2
=5/4
温馨提示:答案为网友推荐,仅供参考