Question

设x=㏒以2为底,3的对数,求2的3x次方减2的-3x次方比上2的x次方减2的-x次方的值.

Answer 1

x=log2(3)

2^x=3

所以原式=[(2^x)^2-(2^x)^(-3)]/[(2^x)-1/(2^x)^2]

=(9-1/27)/(3-1/3)

=121/36