求值(log43+log83)(log32+log92) 注:log后面那为数是底数,最好用通俗易懂的解法.还有一题:lg14-2lg7/3+lg7-lg18
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/06 00:10:40
![求值(log43+log83)(log32+log92) 注:log后面那为数是底数,最好用通俗易懂的解法.还有一题:lg14-2lg7/3+lg7-lg18](/uploads/image/z/11623856-32-6.jpg?t=%E6%B1%82%E5%80%BC%28log43%2Blog83%29%28log32%2Blog92%29+%E6%B3%A8%EF%BC%9Alog%E5%90%8E%E9%9D%A2%E9%82%A3%E4%B8%BA%E6%95%B0%E6%98%AF%E5%BA%95%E6%95%B0%2C%E6%9C%80%E5%A5%BD%E7%94%A8%E9%80%9A%E4%BF%97%E6%98%93%E6%87%82%E7%9A%84%E8%A7%A3%E6%B3%95.%E8%BF%98%E6%9C%89%E4%B8%80%E9%A2%98%EF%BC%9Alg14-2lg7%2F3%2Blg7-lg18)
求值(log43+log83)(log32+log92) 注:log后面那为数是底数,最好用通俗易懂的解法.还有一题:lg14-2lg7/3+lg7-lg18
求值(log43+log83)(log32+log92) 注:log后面那为数是底数,最好用通俗易懂的解法.
还有一题:lg14-2lg7/3+lg7-lg18
求值(log43+log83)(log32+log92) 注:log后面那为数是底数,最好用通俗易懂的解法.还有一题:lg14-2lg7/3+lg7-lg18
lg14-2lg7/3+lg7-lg18
=(lg2+lg7)-2(lg7-lg3)+lg7-(lg9+lg2)
=2lg3-lg9
=lg3²-lg9
=lg9-lg9
=0
⑴ 求值(log4↓3+log8↓3)(log3↓2+log9↓2) 注:log后面那为数是底数;
(log4↓3+log8↓3)(log3↓2+log9↓2
=(lg3/lg4+lg3/lg8)(lg2/lg3+lg2/lg9)
=lg2/lg4+lg2·lg3/lg4·lg9+lg2/lg8+lg2·lg3/lg8·lg9
=1/2+1/4+1...
全部展开
⑴ 求值(log4↓3+log8↓3)(log3↓2+log9↓2) 注:log后面那为数是底数;
(log4↓3+log8↓3)(log3↓2+log9↓2
=(lg3/lg4+lg3/lg8)(lg2/lg3+lg2/lg9)
=lg2/lg4+lg2·lg3/lg4·lg9+lg2/lg8+lg2·lg3/lg8·lg9
=1/2+1/4+1/3+1/6
=30/24
=5/4
⑵ lg14-2lg7/3+lg7-lg18
=lg(14÷49/9×7÷18)
=lg882/882
=lg1
=0
收起