Jee Corner (Main + Advanced) 3

Algebra Level 3

It is given that 1 / 1 4 + 1 / 2 4 + 1 / 3 4 + . . . . . = π 4 / 90 1/1^{4}+1/2^{4}+1/3^{4}+.....\infty=\pi^{4}/90 then, 1 / 1 4 + 1 / 3 4 + 1 / 5 4 + . . . . . = ? 1/1^{4}+1/3^{4}+1/5^{4}+.....\infty=?

π 4 / 45 \pi^{4}/45 89 π 4 / 45 89\pi^{4}/45 π 4 / 96 \pi^{4}/96 89 π 4 / 90 89\pi^{4}/90

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

3 solutions

Akhil Bansal
Nov 22, 2015

Solving jee question in jee style(No pen paper required),
1 1 4 + 1 2 4 + 1 3 4 + + = π 4 90 \dfrac{1}{1^4} + \dfrac{1}{2^4} + \dfrac{1}{3^4} + \ldots + = \dfrac{\pi^4}{90} 1 1 4 + 1 3 4 + = π 4 90 ( 1 2 4 + 1 4 4 + ) \dfrac{1}{1^4} + \dfrac{1}{3^4} + \ldots = \dfrac{\pi^4}{90} - \left(\dfrac{1}{2^4} + \dfrac{1}{4^4} + \ldots \right) .
Therefore, answer must be less than π 4 90 \dfrac{\pi^4}{90} and π 4 96 \dfrac{\pi^4}{96} is the only option satisfying this condition.
If you want actual solution, you can see @Devarsh Wali solution.

Devarsh Wali
Nov 22, 2015

nice way of solving such series.

Jack Right - 5 years, 6 months ago
Sanjwal Singhs
Nov 23, 2015

You can take 1/16 common from the even expansions of the terms that will become pi^4 /90 So finally we get pi^2 /90 (1-1/16) = (pi^2/90 * (15/16)= pi^2 /96

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...