Question

若a=

2

3 -1

，則a²-2a+2的值是______．

Answer 1

a=

2

3 -2

=

2( 3 -2)

( 3 -2)( 3 +2)

=-4-2

3

，
a²-2a+2=（a-1）²+1，
把a=4-2

3

代入（a-1）²+1得（4-2

3

-1）+1=22-12

3

．
故應填22-12

3

．