Explanation for Question 36 From the Math (Calc) Section on the 2018 March Sat
Question 36 says a circle and the X, 2 Y plane has a diameter with end points, 3 negative one, negative three and seven three. 4 If the 0.0 B lies in the circle and B is greater than zero, 5 what is the value of B? So to solve this problem, 6 we're going to need a couple of different formulas. 7 First, we're going to need the formula for a circle or the equation for 8 circle, which I've written at the top here, 9 X minus H squared, plus Y minus K squared is equal to R squared 10 where HK is the center point and R is the radius of the circle. 11 And second, we're going to need the distance formula, 12 which I've written down at the bottom right here. 13 So we're going to start by finding the mid point of the circle so 14 that we can figure out what the equation of this circle actually is. 15 So to do that, I'm just going to take these two points that we've 16 been given in the problem. And I'm just going to figure out what the 17 center of those points is. So the center of seven and negative one is 18 three and the center of negative three and three is zero. 19 So I know that the center point of the circle is three zero, 20 and I can plug that in, into my own equation now, 21 which I'm going to write down here at the bottom. So X minus three 22 squared, plus Y squared, 23 I guess I don't need a print. See there. Plus Y squared is equal 24 to R squared, but I'm not going to write that yet because we still 25 need to figure out what ours. Now we need to find the radius of 26 the...