作业帮求值1.lg25+lg2*lg50+（lg2）²= 2.[（√（lg²3-lg9+1））*（lg√27+lg8-lg√1000）]/（lg0.3*lg1.2）文字表达可能不太清楚,结合图片看吧两个问题都要解(⊙o⊙)哦
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![求值1.lg25+lg2*lg50+（lg2）²= 2.[（√（lg²3-lg9+1））*（lg√27+lg8-lg√1000）]/（lg0.3*lg1.2）文字表达可能不太清楚,结合图片看吧两个问题都要解(⊙o⊙)哦](/uploads/image/z/2988612-36-2.jpg?t=%E6%B1%82%E5%80%BC1.lg25%2Blg2%2Alg50%2B%EF%BC%88lg2%EF%BC%89%26%23178%3B%3D+2.%5B%EF%BC%88%E2%88%9A%EF%BC%88lg%26%23178%3B3-lg9%2B1%EF%BC%89%EF%BC%89%2A%EF%BC%88lg%E2%88%9A27%2Blg8-lg%E2%88%9A1000%EF%BC%89%5D%2F%EF%BC%88lg0.3%2Alg1.2%EF%BC%89%E6%96%87%E5%AD%97%E8%A1%A8%E8%BE%BE%E5%8F%AF%E8%83%BD%E4%B8%8D%E5%A4%AA%E6%B8%85%E6%A5%9A%2C%E7%BB%93%E5%90%88%E5%9B%BE%E7%89%87%E7%9C%8B%E5%90%A7%E4%B8%A4%E4%B8%AA%E9%97%AE%E9%A2%98%E9%83%BD%E8%A6%81%E8%A7%A3%28%E2%8A%99o%E2%8A%99%29%E5%93%A6)
求值1.lg25+lg2*lg50+（lg2）²= 2.[（√（lg²3-lg9+1））*（lg√27+lg8-lg√1000）]/（lg0.3*lg1.2）文字表达可能不太清楚,结合图片看吧两个问题都要解(⊙o⊙)哦
求值1.lg25+lg2*lg50+（lg2）²= 2.
[（√（lg²3-lg9+1））*（lg√27+lg8-lg√1000）]/（lg0.3*lg1.2）
文字表达可能不太清楚,结合图片看吧
两个问题都要解(⊙o⊙)哦
求值1.lg25+lg2*lg50+（lg2）²= 2.[（√（lg²3-lg9+1））*（lg√27+lg8-lg√1000）]/（lg0.3*lg1.2）文字表达可能不太清楚,结合图片看吧两个问题都要解(⊙o⊙)哦
因为lg2+lg5=lg2*5=lg10=1,所以lg5=1-lg2
原式=lg(5^2)+lg2*lg(10*5)+lg2*lg2
=2*lg5+lg2(1+lg5)+lg2*lg2
=(lg2)^2+lg2*lg5+2lg5+lg2
=(lg2)^2+lg2*(1-lg2)+2(1-lg2)+lg2
=2
[√(lg^3-lg9+1)*(lg√27+lg8-lg√1000)]/(lg0.3)*(lg1.2)
={√(lg²3-lg3²+1)*[(1/2)*lg3³+lg2³-(1/2)*lg10³]}/[lg(3/10)*lg(12/10)]
={√(lg²3-2lg3+1)*[(3/2)(lg3)+3*lg2-(3/2)*lg10]}/[lg(3/10)*lg(12/10)]
={√(1-lg3)²*[(3/2)(lg3)+3lg2-(3/2)*1]}/[(lg3-lg10)*(lg12-lg10)], [1-lg3>0]
={(1-lg3)*(3/2)[lg3+2lg2-1]}/[(lg3-1)*(lg12-1)]
=-(3/2)[lg3+lg4-1]/(lg12-1)
=-(3/2)[lg3*4-1]/(lg12-1)
=-(3/2)[lg12-1]/(lg12-1)
=-3/2