20 14 the calculation of 23 questions in the senior high school entrance examination mathematics volume in Kunming, Yunnan Province feels so chaotic. How to calculate? It was the last finale. Solve it. In the plane rectangular coordinate system, the parabola Y = AX 2+BX-3 (A is not equal to 0) intersects with the X axis at points A (-2,0) and B (4 4,0), and intersects with the Y axis at point C, so as to find the analytical expression of the parabola; Point P starts from point A and moves to point B at a speed of 3 unit lengths per second on the AB line, while point Q starts from point B and moves to point C at a speed of 1 unit length per second on the BC line. When one point reaches the end point, the other point stops moving. When the triangle PBQ exists, how many seconds does it move to maximize the area of the triangle PBQ?

This problem is still difficult, and it is a comprehensive problem of quadratic function. The main knowledge points involved are the undetermined coefficient method for solving the quadratic resolution function and the area of triangle. When solving the problem about the moving point, we should pay attention to the range of motion of the point, that is, the range of independent variables. This is the answer/exercise/math /797984. Take a good look at the problem-solving ideas and ponder the answers carefully. I believe you will understand.

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