The sum of the squares of the lengths of the chords intercepted on the circle, x^2+y^2=16, by the lines, x+y=n, n∈ N, where N is the set of all…
JEE Main 2019 — Mathematics Coordinate Geometry
2019mcqmedium
The sum of the squares of the lengths of the chords intercepted on the circle, x2+y2=16, by the lines, x+y=n,n∈N, where N is the set of all natural numbers is:
Official previous-year question
Held on 8 Apr 2019 · Verified 6 Jul 2026.
Options
A
210
B
105
C
320
D
160
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Solution
The length of the perpendicular from centre (0,0) to the line x+y=n is ∣12+I20+0−n∣=2n
Length of intercept =242−(2n)2=64−2n2
⇒ Possible values of n are 1,2,….5
⇒ Sum of the square of lengths of intercepts
=Σn=15(64−2n2)=64×5−2Σn=15n2
=320−2Σn=15n2=320−110=210
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