Sequences & Series · JEE Main previous year questions

2015 2 questions

1. Q42015 · 4 Apr 2015 · Shift 1

   If $m$ is the A.M. of two distinct real numbers $l$ and $n$ ($l,n>1$) and $G_1,G_2$ and $G_3$ are three geometric means between $l$ and $n$, then $G_1^4+2G_2^4+G_3^4$ equals:

   1. A.$4lm{n}^2$
   2. B.$4l^2{m}^2{n}^2$
   3. C.$4l^{2}mn$
   4. D.$4l{m}^{2}n$
   Show answer

   Answer: D

2. Q222015 · 4 Apr 2015 · Shift 1

   The sum of first 9 terms of the series. $$\frac{1^3}{1}+\frac{1^3+2^3}{1+3}+\frac{1^3+2^3+3^3}{1+3+5}+\dots \dots$$

   1. A.$142$
   2. B.$192$
   3. C.$71$
   4. D.$96$
   Show answer

   Answer: D