Question

若lga,lgb是方程2x^2 -4x+1=0的两个根,则（lg(a/b))^2的值是?

Answer 1

lg(a/b)=lga-lgb

lg(a/b))^2=(lga-lgb)^2=（lga+lgb)^2-4lga*lgb=2^2-4*1/2=2

选A