SAT数学抛物线解析

下面是一道关于抛物线的SAT数学题及其解法的内容，非常详细。SAT题中，抛物线是必考的一类，虽然中学课程都有所涉及，还是相对比较抽象，尤其是在理解SAT数学题的表达方式上。下面我们来看看这道关于抛物线的SAT数学题吧。

Read the following SAT test question and then click on a button to select your answer.

The quadratic functionis graphed in the-plane above. Iffor all values of, which of the following could be the coordinates of point?

Answer Choices

(A)

(B)

(C)

(D)

(E)

The correct answer is C

Explanation

The fact thatfor all values ofmeans that the pointis the maximum of the quadratic function, somust be the vertex of the parabola. The parabola intersects the-axis at the pointsand, somust be halfway betweenand. Therefore,. Of the choices, the only one with-coordinate equal tois. Therefore,could be the coordinates of point.