Google Classroom
GeoGebraGeoGebra Classroom

[問題] x² + 2xy + y² + 5x + ay + b > 0

若對於任意實數 x, y,x² + 2xy + y² + 5x + ay + b > 0 恆成立,求 a, b 的條件?
答:a = 5, b > 25/4(提示:利用判別式)