JEE Main 2020 — Sequences And Series Question with Solution
From: JEE Main 2020 (Online) 7th January Evening Slot
Question
Let
,
,
,....... be a G.P. such that
< 0, + = 4 and + = 16.
If , then is equal to:
< 0, + = 4 and + = 16.
If , then is equal to:
Choose an option
Show full solutionCorrect option: B
Correct answer
B-171
Step-by-step explanation
+
= 4
+ r = 4 ...(1)
+ = 16
r2 + r3 = 16 ...(2)
Doing (1) (2), we get
r = 2
If r = 2, then a1 =
If r = -2, then a1 = -4
Given < 0
a1 = -4
= = 4
= 4
= -171
+ r = 4 ...(1)
+ = 16
r2 + r3 = 16 ...(2)
Doing (1) (2), we get
r = 2
If r = 2, then a1 =
If r = -2, then a1 = -4
Given < 0
a1 = -4
= = 4
= 4
= -171
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This is a previous-year question from JEE Main 2020, covering the Sequences And Series chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.