00:01
This is problem number 91 which is related to automobile headlight.
00:07
It is given that the filament of an automobile headlight is at the focus of a parabolic reflector.
00:13
This is the parabolic reflector and this is the focus which sends light out in a straight beam.
00:21
So light is going a straight beam like this.
00:28
Okay, so this is the focus 1 .5 inches.
00:31
Okay so if we set up a coordinate system here it will become x it is y x is so a standard equation of this parabola will look like because this is the vertex 0 .0 according to us standard equation will be y square equal to 4 p x now y square equal to 4 p x uh 4 p and this is okay a question the question was, okay, we have to find the filament of the headlight, find the equation of the cross section of the reflector.
01:18
That is, we have to find the equation of the parabola.
01:22
So, question number a, part a, this is the focus.
01:27
Focus is 1 .5.
01:28
It is 1 .5 inches...