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[發問問題] 2001 LQ 13(c)





From the graph, the value of t when the value of S is greatest, is 4.
But the ans is ~3.8
I hv got which part wrong?

the graph is a curve and should NOT be joined by using straight line.

A note on how to draw the curve "more accurately":

As the graph is a graph for a quadratic eqn, we know that is symmetric.  Therefore, by drawing a horizontal line, say at y=50, you can easily locate 2 intersection points with the cruve.  Then take the mid point of these 2 intersection point on horizontal line.  This is where the max-value of S.

As you know where does the max value occur, then u can draw the curve accordingly (i.e. the curve should reach its max value at the given t value

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