SAT官方每日一题之数学---选择：
Mathematics > Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
The quadratic function
is graphed in the-plane above. If for 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 points
and, somust be halfway betweenand. Therefore,. Of the choices, the only one with-coordinate equal tois. Therefore,could be the coordinates of point.
