SOLUTION: A lamp whose bulb is placed on the focus has a focal diameter of 12 cm. a. find the equation of the parabola. b. find the diameter of the opening 20 cm from the vertex.

Question 1170110: A lamp whose bulb is placed on the focus has a focal diameter of 12 cm.
a. find the equation of the parabola.
b. find the diameter of the opening 20 cm from the vertex.
Answer by AnlytcPhil(1806) (Show Source): You can put this solution on YOUR website!





where (h,k) = (0,0) = the vertex and 4a = focal diameter





The black line is the focal diameter.

We want the length of the red line.

The end points are where y=20













So the red line is twice the absolute value of x.

Answer: , about 30.98

Edwin

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