If a parabola's focus is at (1, −1) and the directrix is at y = 7, what is the equation representing this parabola? x2 − 2x + 16y − 47 = 0
x2 − 47 = 0
x2 − 2x + 16y − 49 = 0
x2 − 2x + 2y2 + 16y − 47 = 0

Correct option: c -> pi/2

Step-by-step explanation:

To have the maximum value of r, we need to have sin(theta) = 1, so we will have r = 3 + 2*1 = 5

For other values of sin(theta), r will be smaller than 5.

So, to have sin(theta) = 1, there is only one possible angle, that is theta = 90 degrees.

To convert from degree to radians, we can use a rule of three:

180 degrees -> pi radians

90 degrees -> x radians

x * 180 = 90*pi

x = 90*pi/180 = pi/2

Correct option: c