For the equation x'(t)=F(z), z=(x,y), with the vector field

F(x,y)= [- x(x^4 + y^4) - y,  x  - y(x^4+y^4)]

prove that the origin is an attractor in the future, i.e., every solution verifies:

limit as t goes to +infinity of z(t) = 0

I need to format my answer as a regular mathematical proof.

Any ideas?

I understand completely how the Playfair cipher works but I'm not sure how to begin to implement it into Maple. Does anyone know how to begin encrypting and decryptin a code using this cipher?

I have a message, "I Didn't See That Double Rainbow!" and i want to encrypt it by making all the characters UpperCase first and removing all punctuation. I used IsUpper to remove the punctuation. Now I want to separate my new scrambled message into BLOCKS OF 5 LETTERS SEPARATED BY SPACES. Any ideas on how to do that using the "printf" command?

with(StringTools):
Alphabet:="THEQUICKBROWNFXJMPSVLAZYDG";
        ...

Use RSA with the modulus n=119 and the exponent e=7, with the 95-character alphabet consisting of the printable ASCII characters to encrypt the word "Yes". Recall that the alphabet is given by

Alphabet:=cat(Select(IsPrintable,convert([seq(i,i=1..255)],bytes)));

so that Y=57, e=69, s=83. Give your encryption as a list of three numbers.