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September 8th, 2013, 08:19 PM   #1
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Eddybob's problem of the week

Here's what Wolfram has if the 10^10 is replaced by a (10^20 = a^2):
http://www.wolframalpha.com/input/?i=so ... %3D0+for+x

YIKES
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September 9th, 2013, 02:20 PM   #2
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Re: Eddybob's problem of the week

Weird. Where do all the decimals come from?
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September 9th, 2013, 07:06 PM   #3
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Re: Eddybob's problem of the week

Get the roots to 4 decimal places. I understand that the exact values are quite complicated.
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September 9th, 2013, 08:15 PM   #4
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Re: Eddybob's problem of the week

Quote:
Originally Posted by CRGreathouse
Weird. Where do all the decimals come from?
Ya ain't seen nuttin' yet; go enter: x^4-(2*10^10-1)*x^3-x+10^20+10^10-1=0
here: http://www.numberempire.com/equationsolver.php
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September 10th, 2013, 12:21 PM   #5
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Re: Eddybob's problem of the week

x^4 - (2*10^10 - 1) * x^3 - x + 10^20 + 10^10 - 1 = 0
Let k = 10^10; then we have a quadratic:
k^2 + (1 - 2x^3)k + x^4 + x^3 - x - 1 = 0

2k = 2x^3 - 1 +- SQRT(4x^6 - 4x^4 - 8x^3 + 4x + 5)

Ya, I know...so what!?
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September 10th, 2013, 03:23 PM   #6
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Re: Eddybob's problem of the week

You really know how to cheat, do you?
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September 10th, 2013, 06:53 PM   #7
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Re: Eddybob's problem of the week

If you say so...
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