lga,lgb是方程2x²-4x+3=0的两个根
韦达定理:lga+lgb=2
lgalgb=3/2
(lga/b)²
=(lga-lgb)²
=lg²a-2lgalgb+lg²b
=(lga+lgb)²-4lgalgb
=2²-4×3/2
=4-6
=-2
答案:-2
lga,lgb是方程2x²-4x+3=0的两个根
韦达定理:lga+lgb=2
lgalgb=3/2
(lga/b)²
=(lga-lgb)²
=lg²a-2lgalgb+lg²b
=(lga+lgb)²-4lgalgb
=2²-4×3/2
=4-6
=-2
答案:-2