A = 1 + 1 + 1 + 1 + 1 + ⋯ e − 3 π e − 2 π e − π 1
Find A .
Note: Don't use any programming or software such as Wolfram Alpha.
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How did they prove this?
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The Mathworld page for the R-R CF refers to two papers, one in 2001 and the other in 2004.
It can be proved that the function
ρ ( q ) = 1 + 1 + 1 + 1 + 1 + . . . . . q 3 q 2 q 1 is continuous ,and of infinite class over the positive real numbers.( In complex field it has singularities.
So, ρ ( q ) = ρ ( 0 ) + q ρ ′ ( 0 ) + 2 ! q 2 ρ ′ ′ ( 0 ) + 3 ! q 3 ρ ′ ′ ′ ( 0 ) + . . . .
We get, ρ ( 0 ) = 2 , ρ ′ ( 0 ) = − 1 , ρ ′ ′ ( 0 ) = 2 , ρ ′ ′ ′ ( 0 ) = − 4 , . . . .
So, ρ ( q ) = 2 − q + q 2 − q 4 + q 5 − q 6 + q 7 − q 9 + q 1 0 − q 1 1 + q 1 2 − q 1 4 . . . . .
Here q 3 , q 8 , q 1 3 , q 2 3 , . . . terms are invalid. But what is the pattern? Yes. It is similar to Fibonacci sequence. See, the missing powers are 3 , 8 , 1 3 , 2 3 . . . and ( 3 + 8 ) + 2 = 1 3 ; ( 8 + 1 3 ) + 2 = 2 3 . . . . So, missing numbers will follow the Fibonacci sequence but ′ 2 ′ ahead.
ρ ( e − π ) ≈ ( 2 − e − π + e − 2 π − e − 4 π + q − 5 π ) ≈ 1 . 9 5 8 6 .
I know we need to solve it manually but is there any Python program to solve this, please share.
I have done it with an Excel spreadsheet, if you are interested.
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Thank you. Everything works. I am recently learning python and interested in learning other languages too so l thought there could be a certain program. Thank you always.
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We have A = 1 + e 5 1 π R ( e − π ) where R ( q ) is the Rogers-Ramanujan continued fraction. It is a remarkable fact that R ( e − π ) = 8 1 ( 3 + 5 ) ( 4 5 − 1 ) ( 1 0 + 2 5 − ( 3 + 4 5 ) ( 4 5 − 1 ) ) and so we have an exact expression for A . To 1 0 significant figures, we have A = 1 . 9 5 8 6 5 0 1 8 2 .