Power Function Oddity

07222019, 07:37 PM
Post: #1




Power Function Oddity
On the Home screen:
4^4^4^4 returns 9.999999999999E499 But 4^4, Enter Ans^4, Enter Ans^4, Enter returns answer 3.40282366921E38 Which one is correct? 

07222019, 08:03 PM
Post: #2




RE: Power Function Oddity
I guess it'll be an overflow.
The 3.xxE38 is certainly incorrect. WolframAlpha claims the answer is a number that contains 8.07E158 digits.. Also, after 10 minutes, my xMaxima has yet not returned any answer.. Esben 28s, 35s, 49G+, 50G, Elektronika MK52 & MK61 

07222019, 08:14 PM
(This post was last modified: 07222019 08:15 PM by DA74254.)
Post: #3




RE: Power Function Oddity
Hmm, let me edit my answer a little.
Both *may* be correct. Depending on how you "set up" your expression. By ^4 for each intermediate calculation, you get a first level exponetiation, whereas, if you "stack" the ^4's you'll get a really high number. Your latter answer would be 4^4=256^4=4294967296^4=340282366920938463463374607431768211456. But the "stacking would equal 4^134078079299425970995740249982058461274793658205923933777235614437217640\ 300735469768018742981669034276900318581864860508537538828119465699464336490060\ 84096 Edit: Here's the link to WA: https://www.wolframalpha.com/input/?i=4%5E4%5E4%5E4 Esben 28s, 35s, 49G+, 50G, Elektronika MK52 & MK61 

07222019, 08:35 PM
Post: #4




RE: Power Function Oddity
Exponentiation operator is evaluated from right to left:
4^4^4^4 = 10^(4^4^4 * log10(4)) ≈ 10^8.0723e153 

07232019, 12:11 AM
(This post was last modified: 07232019 10:44 AM by toml_12953.)
Post: #5




RE: Power Function Oddity
(07222019 08:35 PM)Albert Chan Wrote: Exponentiation operator is evaluated from right to left: If it's evaluated right to left, wouldn't it be: 4^(4^(4^4)) which is 4^1.340780792994e+154. Too big for the Prime. Tom L I think therefore I amDescartes I think therefore you areGorgias You're not here to thinkArmy Sergeant 

07232019, 05:54 AM
Post: #6




RE: Power Function Oddity
(07222019 07:37 PM)Eddie W. Shore Wrote: 4^4^4^4 returns 9.999999999999E499 4^4^4^4 returns 9.999999999999E499 4^4, Enter 4^Ans, Enter 4^Ans, Enter returns answer 9.999999999999E499 Viga C  TD  FB 

07232019, 07:40 AM
(This post was last modified: 07232019 07:42 AM by ijabbott.)
Post: #7




RE: Power Function Oddity
4^4^4^4 Enter is 4^(4^(4^4)), but 4^4 Enter Ans^4 Enter Ans^4 Enter is ((4^4)^4)^4.
I.e. ^ associates righttoleft, not lefttoright. — Ian Abbott 

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