<p>I used something I had learned in calculus, but not really calculus in 4d</p>
<p>4d? how was it calculus… wasn’t it just plugging in and trying the numbers?</p>
<p>^Umm, that would have taken way too much time. </p>
<p>4(d) asked for the maximum of a function given in part 4(c). Since the function was a quadratic, the maximum occurs at the critical number. So to find that, take the derivative of the function, set it equal to zero, and solve.</p>