<p>Sorry to post in the wrong place, but nobody seems to be able to answer my Calculator question (for Calculus) in the Math AP threads, so if somebody can please help here, I would greatly appreciate it :)</p>
<p>The question is "At what instant does the particle, which moves along a line in such a way that at time t, 1 is less than or equal to "t" which is less than or equal to 8, reaches its maximum speed?</p>
<p>I know that I have to set the absolute value of the velocity equal to 0.</p>
<p>I used the solve key and got weird answers of 5.204, 51.893, and 67.6.</p>
<p>The correct answer is supposed to be 5.896, which I got when I graphed the equation.</p>
<p>Why doesn't the Solve key work for this?</p>
<p>(i'm using the TI89 by the way)</p>
<p>THanks for your help!!!!!</p>