当a=1/2时,代数式a²+1/a+2a的值是

问题描述:

当a=1/2时,代数式a²+1/a+2a的值是

13/4

a=1/2
a²+1/a+2a
=1/4+2+1
=13/4

a²+1/a+2a
= (1/2)²+1/(1/2)+2x1/2
=1/4+2+1
=3又1/4