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+--- Thread: Power Function Oddity (/thread-13317.html)
Power Function Oddity - Eddie W. Shore - 07-22-2019 07:37 PM
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?
RE: Power Function Oddity - DA74254 - 07-22-2019 08:03 PM
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..
RE: Power Function Oddity - DA74254 - 07-22-2019 08:14 PM
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
RE: Power Function Oddity - Albert Chan - 07-22-2019 08:35 PM
Exponentiation operator is evaluated from right to left:
4^4^4^4 = 10^(4^4^4 * log10(4)) ≈ 10^8.0723e153
RE: Power Function Oddity - toml_12953 - 07-23-2019 12:11 AM
(07-22-2019 08:35 PM)Albert Chan Wrote: Exponentiation operator is evaluated from right to left:
4^4^4^4 = 10^(4^4^4 * log10(4)) ≈ 10^8.0723e153
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.
RE: Power Function Oddity - Carlos295pz - 07-23-2019 05:54 AM
(07-22-2019 07:37 PM)Eddie W. Shore Wrote: 4^4^4^4 returns 9.999999999999E499
But
4^4, Enter
Ans^4, Enter
Ans^4, Enter returns answer 3.40282366921E38
4^4^4^4 returns 9.999999999999E499
4^4, Enter
4^Ans, Enter
4^Ans, Enter returns answer 9.999999999999E499
RE: Power Function Oddity - ijabbott - 07-23-2019 07:40 AM
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 right-to-left, not left-to-right.