(log2 3+log4 9+.+以2的n次方为底3的n次方的对数）乘以log9 8的n次方根 [利用对数的换底公式]
= [ln3/ln2 + 2ln3/(2ln2) + ...+ nln3/(nln2)][nln8/(2ln3)]
= [ln3/ln2][1 + 1 + ...+ 1][3nln2/(2ln3)]
= n[3n/2]
= 3n^2/2