已知20的x次方=1000,50的y次方=1000,求(x+y)/xy,快
问题描述：
已知20的x次方=1000,50的y次方=1000,求(x+y)/xy,快
答
20^x = 100050^y = 1000x = 3/lg20 =3 / (1+lg2)y = 3/lg50 = 3 / (1+lg5)(x+y) / (xy)= (3/lg20 + 3/ lg50) / (9 / lg20 lg50)= (3lg50+3lg20)/(lg20 lg50) / (9 / lg20 lg50)= (lg50+lg20)/3= (1+lg5+1+lg2)/3= 3/...看不懂，这是几年级的？按所问的题目，应该能看懂？lgN 是常用对数？不懂吗？例如： lg1000 =3