负整数指数幂
问题描述：
负整数指数幂
-2 2 2 -2 -3
a b ( a b )
1
x __________
( 1-_____)÷ 2
x-1 x - x
a的-2次幂b的2次幂 乘以 （a的2次幂b的-2次幂）的-3次幂
(1-x-1分之x)除以 x的2次幂-2分之1
答
1.
a^(-2)*b^2*[a^2*b^(-2)]^(-3)
=a^(-2)*b^2*a^(-6)*b^6
=a^(-2-6)*b^(2+6)
=a^(-8)*b^8;
2.
[1-x/(x-1)]÷[1/(x^2-2)]
=[(x-1-x)/(x-1)]*(x^2-2)
=-(x^2-2)/(x-1)
=(2-x^2)/(x-1).