PDA

View Full Version : another problem


abia ubong
May7-05, 11:51 AM
how do i find the area of a rectanglewith sides 400root of 400 raised continously to itself like x^x^x^..and 800root of 800 raised also to itself continouslylike y^y^y...
leave answer in whole number not exponent

dextercioby
May7-05, 12:00 PM
What do those "..." mean...?I can assume you'd have to evaluate

400^{400^{400^{...}}}\cdot 800^{800^{800^{...}}}

Daniel.

HallsofIvy
May7-05, 12:03 PM
Do you have any reason to think that such a sequence converges?

dextercioby
May7-05, 12:22 PM
Read mathworld's page on the power tower.I'm sure u'll find the upper limit for the convergence interval,that is,of course,if u meant the infinite superpower of 400 and 800 respectively.

Daniel.

saltydog
May7-05, 12:41 PM
Abia, consistent no doubt. I think you mean a power tower like:

"The 400'th root of 400"

\sqrt[400]{400}\approx 1.01509

I think that's in the range of convergence.

Edit: The 800 one too for that matter. :smile:

abia ubong
May8-05, 01:59 PM
area of rectangle with lenght x^x^x^x^x.....
and breath y^y^y^y^y^y..... where x is 400^ 1/400 and y is 800^ 1/800.
leaving answer in whole number not decimal or exponent

saltydog
May8-05, 02:46 PM
leaving answer in whole number not decimal or exponent

Hello Abia. Yea, leaving it in whole numbers . . . hum . . . how about expressing the power towers in terms of Lambert W-functions (which can be done and in whole numbers), and in this way then the area is just a product of two such expressions.

mathelord
May8-05, 03:02 PM
do not understand
pls explain

saltydog
May8-05, 03:12 PM
do not understand
pls explain

Check out Power Towers, and Lambert W-functions in MathWorld. Try that first.