# trig

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The cross section of a television antenna dish is a parabola. A dish has a receiver that is located at the focus, 4 ft. above the vertex.

Find the equation. (which I did) -- x^2 = 8y

If the dish is 8 feet wide, how deep is it?

• trig -

so x = +/- 4 if 8 wide
what is y ?
16 = 8 y
y = 2

• trig -

Wow. Do I just substitute x with 8, and then solve to get y=5?

• trig -

Oops nevermind, sorry.

• trig -

No, x is half the width.

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