PSQ is focal chord of the ellipse 4x2 + 9y2 = 36 such that SP = 4. If S’ is the another focus, write the value of S’Q.
Given that PSQ is the focal chord of the ellipse 4x2 + 9y2 = 36.
It is also given that SP = 4. We need to find the value of S’Q, where S and S’ are foci.
Given ellipse is rewritten as 
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We got a2 = 9, a = 3 and b2 = 4.
We know that semi latus rectum is the harmonic mean of any two segments of focal chord.
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We know that SQ + S’Q = 2a
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