Consider P ( x ) = 1 7 2 9 x n + a n − 1 x n − 1 + ⋯ + a 1 x + a 0 , ∀ a i ∈ R with 0 ≤ i ≤ n − 1 .
Let α 1 , α 2 , … , α n be its n roots such that i = 2 ∏ n ( α 1 − α i ) = k where k is some real number other than 0 .
If L = x → α 1 lim ( 1 + P ( x ) ) 1 / ( x − α 1 ) where α 1 is a real root, then evaluate k ln L to correct two decimal places.
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Damn! I forgot the constant 1729 while writing P(x).
BTW nice problem.
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Lol, even I had forgot about the constant when I first attempted this problem :P
well yeah!i was wondering why its not 1 till i realised i forgot the constant 1729!
Why you gave answer as decimals??
I think my answer 1729 was not accepted as it show ans 1729.00
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We can express P ( x ) = 1 7 2 9 i = 1 ∏ n ( x − α i ) and we can write L as x − > α 1 lim ( 1 + 1 7 2 9 i = 1 ∏ n ( x − α i ) ) 1 7 2 9 i = 1 ∏ n ( x − α i ) 1 7 2 9 i = 2 ∏ n ( x − α i ) . Note that as x → α 1 , 1 7 2 9 i = 1 ∏ n ( x − α i ) → 0 , so the limit L is equivalent to the famous limit x → 0 lim ( 1 + x ) 1 / x = e . So finally, we have:
L = e x → α 1 lim 1 7 2 9 i = 2 ∏ n ( x − α i ) = e 1 7 2 9 k and we have k ln L = 1 7 2 9 .