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thereddevils
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Homework Statement
(p,a) , (q,b) and (r,c) are the coordinates of three points on the parabola y^2=3x. If the x-coordinate for these three points form a geometric progression whereas the corresponding y-coordinate form an arithmetic progression, find the common ratio of the geometric progression.
Homework Equations
The Attempt at a Solution
q^2=rp and 2b=c+a
Substitute those points into the parabola to get a^2=3p , b^2=3q and c^2=3r
q^2=rp
(b^4/9)=((a^2c^2)/9)
b^4=a^2c^2
b^2= +/- ac
This part confuses me. I would get a=c if i take it to be positive.
Then substituting into 2b=c+a, that would be b=a=c ?