Question

A light house uses a parabolic reflector that is 1 m in diameter how deep should the reflectpr be if the light source is placed halfwayy between the vertex and the plane of the rim?

Answer 1

write the equation y=a *x^2
for x= 0.5 y = 0.25 a and y focus ( light source )= 0.125a
but in a a parabola y =ax^2+bx+c y focus =(4ac-b^2 +1)/4a so in this case = 1/4a
so 1/4a= 0.125a and a^2=2 so a = sqrt2 and depth = 0.35.36 m

http://in.answers.yahoo.com/question/index?qid=20101119033031AAmzuSC

Answer 2

@ali110

Answer 3

the answer here in the book is y^2 = 36x. i dont understand how to get this

Answer 4

just round it.

Answer 5

Answer: 9 inches from the vertex; how?

Answer 6

36x(approx.)

Answer 7

can you draw the sketch? :)

Answer 8

thank you

Answer 9

a large reflecting telescope has a parabolic mirror that is 4 meters in diameter