tony987852

已知a的5/2次方=3的-2次方，求a的4次方Xa的-1/2次方.

log(a^5/2) = log(3^-2)
5/2 log(a) = -2log3
log(a) = -4(log3) / 5
a = 10^ [-4(log3) / 5]

a^4 * a^-1/2
= {10^ [-4(log3) / 5]}^4 * {10^ [-4(log3) / 5]}^-1/2

展開（X+1）（X+2)（X+3）

(x+1)(x+2)(x+3)
=6+11 x+6 x^2+x^3

(好似係)