I am sure that by now, all the Mathematics-loving members of ISC have realized that the shrewd king is not at all ready to hand over the beautiful princess to anyone. But he immensely enjoys the fun when his subjects waste their time to try to solve this insoluble equation.
Now let us come to the equation. There are three variables but only one equation. So, the equation cannot be attempted by any conventional method. We have to try something unconventional.
First, let us consider positive integers as directed by the king. Let us go to the right hand side of the given equation. In the right hand side of the equation, the value is given 42. 42 can be factorized in the following manner:-
42=1*42
42=2*21
42=3*14
42=6*7
(a) If (x^3 + y^3 + z^3) = 1, then (x + y + z) must be equal to 42, since their product should be 42. However, it is impossible to find three positive integers whose sum is 42 (when the sum of their cubes is 42).
(b) If (x^3 + y^3 + z^3) = 2, then (x + y + z) is equal to 21 since their product should be 42. Again, it is impossible to find three such positive integers whose sum is 21 (when the sum of their cubes is 2)
(c) If (x^3 + y^3 + z^3) = 3, then (x + y + z) is equal to 14 since their product should be 42. Again, it is impossible to find three such positive integers whose sum is 14 (when the sum of their cubes is 3).
And so on ...............................
Checking all these possibilities as per the factorization of 42, we find there is no such set of three positive integers which satisfies the given equation.
So, no princess for anyone.
Those who have unlimited time, would try to solve the equation with positive fractions, but with no result. A great Mathematics-lover of this site has even attempted to solve it with negative fractions!!!
Umesh-Sir very quickly understood that the equation can't be solved using his own unconventional method.
Although, those members who attempted the equation, won't get the princess, they will all get virtual gift from me for their valiant efforts.
(a) Those who have forgotten Noakhali, how can they protest Sandeshkhali?
(b) Have no fear of perfection - you'll never reach it. ---------- Salvador Dali