1 − 4 1 + 8 1 − 1 0 1 + 1 4 1 − 1 6 1 + ⋯ = ?
The problem is original
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.
There are infinitely many sequences that can be generated from 1, -4, +8, ... How were we to know you meant this one?
The above series can be written as:
1 + Σ n = 0 ∞ 6 n + 8 1 − 6 n + 4 1 ;
or 1 + Σ n = 0 ∞ ∫ 0 1 x 6 n + 7 − x 6 n + 3 d x ;
or 1 + ∫ 0 1 ( x 7 − x 3 ) ⋅ Σ n = 0 ∞ x 6 n d x ;
or 1 + ∫ 0 1 1 − x 6 x 7 − x 3 d x ;
or 1 − ∫ 0 1 ( x 3 + 1 ) ( x 3 − 1 ) x 3 ( x 4 − 1 ) d x ;
or 1 − ∫ 0 1 ( x + 1 ) ( x 2 − x + 1 ) ( x − 1 ) ( x 2 + x + 1 ) x 3 ( x 2 + 1 ) ( x + 1 ) ( x − 1 ) d x ;
or 1 − ∫ 0 1 x 4 + x 2 + 1 x 5 + x 3 d x ;
or 1 − ∫ 0 1 x − x 4 + x 2 + 1 x d x ;
or 1 − ∫ 0 1 x − ( x 2 + 1 / 2 ) 2 + 3 / 4 x d x ;
or 1 − [ 2 x 2 − 3 1 arctan ( 3 2 x 2 + 1 ) ∣ 0 1 ] ;
or 2 1 + 6 3 π .
Problem Loading...
Note Loading...
Set Loading...
I found this interesting
t a n x = 2 π − x 1 − 2 π + x 1 + 2 3 π − x 1 − 2 3 π + x 1 + 2 5 π − x 1 − ⋯
This lemma is a consequence of "Euler’s product" formula
taking x = 6 π
We will end up with
t a n ( 6 π ) = 2 π 6 − 4 π 6 + 8 π 6 − 1 0 π 6 + 1 4 π 6 − ⋯
So 6 √ 3 π = 2 1 − 4 1 + 8 1 − 1 0 1 + 1 4 1 − 1 6 1 + ⋯
By Adding 2 1 we can get our answer
Answer will be 6 √ 3 π + 2 1