已知以a为底x的对数+3倍的以x为底a的对数-以x为底y的对数=3（a>1）若设x=a的t次方.试用a.t表示y当a=16y的取值范围?

Question

已知以a为底x的对数+3倍的以x为底a的对数-以x为底y的对数=3（a>1）
若设x=a的t次方.试用a.t表示y 当a=16 y的取值范围?

Answer 1

X = a^t=> log(a)x = t3log(x)a = 3log(a)a/log(a)x= 3/tlog(x)y = log(a)y/log(a)x = log(a)y/t代入原式有：t + 3/t - log(a)y/t = 3=> t^2 – 3t +3 = log(a)y=> y = a(t^2 – 3t +3)对数中（）内的是底若a=16 代...