你是否还记得中学数学里那个熟悉的抛物线y=ax^2+bx+c？它的开口方向由a决定，与x轴的交点由判别式Δ决定。这就引出了一个核心问题：如何判断一个多项式的值是恒正、恒负还是有正有负？

This jingle has helped generations of algebra students recall the quadratic formula that solves every equation of the form $latex ax^2+bx+c=0$. The formula is as ...

All quadratic functions have the same type of curved graphs with a line of symmetry. The graph of the quadratic function \(y = ax^2 + bx + c \) has a minimum turning point when \(a \textgreater 0 \) ...

All quadratic functions have the same type of curved graphs with a line of symmetry. The graph of the quadratic function \(y = ax^2 + bx + c\) is a smooth curve with one turning point. The turning ...

Everyone learns (and some readers maybe still remember) the quadratic formula. It’s a pillar of algebra and allows you to solve equations like Ax 2 +Bx+C=0. But just because you’ve used it doesn’t ...