Explanation for Question 36 From the Math (Calc) Section on the 2019 October Sat
So now a number 36, we're told that we have a, 2 um, an object that's traveling a distance to D um, 3 in terms of time T and we're told that it's a quadratic equation, 4 right? So perhaps a general form of this would look like a times T 5 squared, plus B times T plus C is equal to zero, 6 right? So this is kind of like the a X squared plus BX plus 7 C, but instead of writing an exit, 8 we've put in T's because that's what we're talking about. 9 And actually it shouldn't be as equal to zero. It should be as equal 10 to the distance, right? Because this is an equation for the distance. 11 And so the first thing that we know is that at time T when 12 it's zero, we're at zero meters, 13 right? So when T is zero times zero plus B times zero plus 14 C is equal to zero. 15 Then we already know what one term in our equation is, 16 right? Because both of these will be zero. There you go away. 17 So it tells us that C is equal to zero. So we actually don't 18 even have to worry about the C all we have to worry about, 19 just to clarify, this should just be a T it shouldn't be T squared. 20 Um, so all we have to worry about here. So the a T squared 21 and the BT, so you have a T squared plus B T is equal 22 to the distance. And so you now notice, 23 right? We have an a and a B. And so those are, 24 what's getting in the way of us solving for 30 seconds, 25 right? Because we don't know what a is, and we don't know what B 26 is and the way that we can do this. 27 Now, since we notice we h...