Find all possible integer solutions that satisfy this system of equations:
a+b+c=1
a3+b3+c2=1
There is an infinite number of solutions of the form (k, -k, 1).
Algebraic manipulation shows 4 more solutions:
c = 1-a-b
c^2 = 1 + a^2 + b^2 + 2(ab - a - b)
a^3 + b^3 + c^2 = a^3+b^3+ 1 + a^2 + b^2 + 2(ab - a - b) = 1
a^3 + b^3 + a^2 + b^2 + 2(ab - a - b) = 0
(a^3 + a^2 - 2a) + (b^3 + b^2 - 2b) + 2ab = 0
a(a+2)(a-1) + b(b+2)(b-1) + 2ab = 0
By inspection if either a or b is zero, then the other (b or a) can be {0, 1, -2} and the equation is satisfied giving 6 solutions, though 2 of them are both (0,0,1) and are included in the infinite set noted above. The other four:
(0,1,0), (0,-2,3), (1,0,0), (-2,0,3).
There are 2 others that I didn't find until running the program. I suspect further algebraic manipulation would find them. [Edit: it looks like broll already did so]
The complete set:
(a,b,c)
(k, -k, 1) for all integers k
(-3,-2,6)
(-2,-3,6)
(-2,0,3)
(0,-2,3)
(0,1,0)
(1,0,0)
----------------------
big = 1000
for a in range(-big,big+1):
for b in range(-big,big+1):
if a == -b:
continue
c = 1-a-b
if a**3 + b**3 + c**2 == 1:
print('({},{},{})'.format(a,b,c))
Edited on October 1, 2023, 8:46 am
|
Posted by Larry
on 2023-10-01 08:45:09 |