∵ |a^n|=1/2,|b^n|=3
∴ (|a^n|)²=(a^n)²=(1/2)²=1/4,(|b^n|)²=(b^n)²=3²=9
∴(ab)^2n=a^2n×b^2n
=(a^n)²×(b^n)²
=(1/4)×9
=9/4再问一题x²+x^-2=？你好：x²+x^-2=(x²+2+x^-2)-2=(x+x^-1)²-2x²+x^-2=(x²-2+x^-2)+2=(x-x^-1)²+2