log2^3·log3^4·log4^5·log5^2
=(logx^3/logx^2)*(logx^4/logx^3)*(logx^5/logx^4)*(logx^2/logx^5)
=1
p.s
x是任意大于0的数
换底公式：
logx^y/logx^z=logz^y