lg4怎么等于1了!有2个式子:lg25+lg2lg50(①式) lg25+lg2lg50+lg4(②式)=lg5^2+lg2(lg5+lg10) =2lg5+lg2(lg50+lg2)=lg5^2+lg5lg2+lg2 =2lg5+lg100lg2=lg5(lg5+lg2)+lg2 =2(lg5+lg2)=lg5x1+lg2 =2x1=lg5+lg2 =2=1那么②式-①式=lg25+lg2lg50
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/30 04:33:19
![lg4怎么等于1了!有2个式子:lg25+lg2lg50(①式) lg25+lg2lg50+lg4(②式)=lg5^2+lg2(lg5+lg10) =2lg5+lg2(lg50+lg2)=lg5^2+lg5lg2+lg2 =2lg5+lg100lg2=lg5(lg5+lg2)+lg2 =2(lg5+lg2)=lg5x1+lg2 =2x1=lg5+lg2 =2=1那么②式-①式=lg25+lg2lg50](/uploads/image/z/1008905-41-5.jpg?t=lg4%E6%80%8E%E4%B9%88%E7%AD%89%E4%BA%8E1%E4%BA%86%21%E6%9C%892%E4%B8%AA%E5%BC%8F%E5%AD%90%EF%BC%9Alg25%2Blg2lg50%EF%BC%88%E2%91%A0%E5%BC%8F%EF%BC%89+lg25%2Blg2lg50%2Blg4%EF%BC%88%E2%91%A1%E5%BC%8F%EF%BC%89%3Dlg5%5E2%2Blg2%28lg5%2Blg10%29+%3D2lg5%2Blg2%28lg50%2Blg2%29%3Dlg5%5E2%2Blg5lg2%2Blg2+%3D2lg5%2Blg100lg2%3Dlg5%28lg5%2Blg2%29%2Blg2+%3D2%28lg5%2Blg2%29%3Dlg5x1%2Blg2+%3D2x1%3Dlg5%2Blg2+%3D2%3D1%E9%82%A3%E4%B9%88%E2%91%A1%E5%BC%8F-%E2%91%A0%E5%BC%8F%3Dlg25%2Blg2lg50)
lg4怎么等于1了!有2个式子:lg25+lg2lg50(①式) lg25+lg2lg50+lg4(②式)=lg5^2+lg2(lg5+lg10) =2lg5+lg2(lg50+lg2)=lg5^2+lg5lg2+lg2 =2lg5+lg100lg2=lg5(lg5+lg2)+lg2 =2(lg5+lg2)=lg5x1+lg2 =2x1=lg5+lg2 =2=1那么②式-①式=lg25+lg2lg50
lg4怎么等于1了!
有2个式子:
lg25+lg2lg50(①式) lg25+lg2lg50+lg4(②式)
=lg5^2+lg2(lg5+lg10) =2lg5+lg2(lg50+lg2)
=lg5^2+lg5lg2+lg2 =2lg5+lg100lg2
=lg5(lg5+lg2)+lg2 =2(lg5+lg2)
=lg5x1+lg2 =2x1
=lg5+lg2 =2
=1
那么②式-①式=lg25+lg2lg50+lg4-lg25-lg2lg50=lg4=2-1=1
结果变成 lg4=1 了 (lg4=0.09062.计算器按的)
可是上面的式子也好像没错
那这是怎么回事啊?
lg4怎么等于1了!有2个式子:lg25+lg2lg50(①式) lg25+lg2lg50+lg4(②式)=lg5^2+lg2(lg5+lg10) =2lg5+lg2(lg50+lg2)=lg5^2+lg5lg2+lg2 =2lg5+lg100lg2=lg5(lg5+lg2)+lg2 =2(lg5+lg2)=lg5x1+lg2 =2x1=lg5+lg2 =2=1那么②式-①式=lg25+lg2lg50
2式第一步错了,括号里应该是(lg50+2)而不是(lg50+lg2)
lg4 != lg2 * lg2
1. lg4 = 2lg2 > lg2lg2. 所以②式错了.
2. lg25 = 2lg5 > (lg5)^2. 所以①式也错了.
自重= =.
=lg5^2+lg5lg2+lg2
=lg5(lg5+lg2)+lg2
这步错,lg(5^2)该是2 lg5
注意 lg5^2与 lg(5^2)时不一样的
lg4=lg2+lg2,而不是lg2*lg2。
lg25=lg(5^2)=2lg5≠lg5*lg5
lg25+lg2lg50+lg4
=2lg5+lg2(lg50+2)【这里lg4=2lg2,而不是(lg2)^2】
=2lg5+lg2(1+lg5+2)【lg2*lg50≠lg2+lg50=2】
所以你两个结果都是错的
一式lg5^2+lg5lg2=lg5(lg5+lg2)错了
二式lg2lg50+lg4=lg2(lg50+lg2)又错了