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Question 822806: A reflecting telescope has a parabolic mirror for which the distance from the vertex to the focus is 30 ft. if the distance across the top of the mirror is 64 in., how deep is the mirror at the center?
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! A reflecting telescope has a parabolic mirror for which the distance from the vertex to the focus is 30 ft. if the distance across the top of the mirror is 64 in., how deep is the mirror at the center?
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Use basic equation for a parabola that opens upward with vertex at the origin (0,0).
x^2=4py
p=30ft=360 inches(distance above vertex on the axis of symmetry,x=0.
4p=1440
solve for y at the point where x=32(half the distance across the top)
32^2=1440y
y=1440/32^2≈1.406
how deep is the mirror at the center? 1.406 inches
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