If [tex][tex]$x^3 + y^3 + z^3 = 1$[/tex][/tex], then prove that:
[tex]\[
\left( \frac{a^x}{a^{-y}} \right)^{x^2 - xy + y^2} \times \left( \frac{a^y}{a^{-z}} \right)^{y^2 - yz + z^2} \times \left( \frac{a^z}{a^{-x}} \right)^{z^2 - zx + x^2} = a^2
\][/tex]



Answer :

Given that [tex]\( x^3 + y^3 + z^3 = 1 \)[/tex], we need to prove that:
[tex]\[ \left( \frac{a^x}{a^{-y}} \right)^{x^2 - xy + y^2} \times \left( \frac{a^y}{a^{-z}} \right)^{y^2 - yz + z^2} \times \left( \frac{a^z}{a^{-x}} \right)^{z^2 - zx + x^2} = a^2 \][/tex]

### Simplify Each Term

1. Simplify the bases:
[tex]\[ \frac{a^x}{a^{-y}} = a^{x - (-y)} = a^{x + y} \][/tex]
[tex]\[ \frac{a^y}{a^{-z}} = a^{y - (-z)} = a^{y + z} \][/tex]
[tex]\[ \frac{a^z}{a^{-x}} = a^{z - (-x)} = a^{z + x} \][/tex]

2. Rewrite the equation with simplified bases:
[tex]\[ \left( a^{x + y} \right)^{x^2 - xy + y^2} \times \left( a^{y + z} \right)^{y^2 - yz + z^2} \times \left( a^{z + x} \right)^{z^2 - zx + x^2} \][/tex]

3. Combine the exponents:
Recall that [tex]\((a^m)^n = a^{mn}\)[/tex]:
[tex]\[ a^{(x+y)(x^2 - xy + y^2)} \times a^{(y+z)(y^2 - yz + z^2)} \times a^{(z+x)(z^2 - zx + x^2)} \][/tex]

4. Add the exponents:
Since the bases are the same ([tex]\( a \)[/tex]), we can combine the exponents:
[tex]\[ a^{(x+y)(x^2 - xy + y^2) + (y+z)(y^2 - yz + z^2) + (z+x)(z^2 - zx + x^2)} \][/tex]

### Expand and Simplify the Exponents

Next, we'll expand the expressions inside the exponents:

[tex]\[ (x+y)(x^2 - xy + y^2) \][/tex]
Expanding, we get:
[tex]\[ x^3 - x^2y + xy^2 + x^2y - xy^2 + y^3 = x^3 + y^3 \][/tex]

Similarly for:
[tex]\[ (y+z)(y^2 - yz + z^2) \][/tex]
Expanding, we get:
[tex]\[ y^3 - y^2z + yz^2 + y^2z - yz^2 + z^3 = y^3 + z^3 \][/tex]

And:
[tex]\[ (z+x)(z^2 - zx + x^2) \][/tex]
Expanding, we get:
[tex]\[ z^3 - z^2x + zx^2 + z^2x - zx^2 + x^3 = z^3 + x^3 \][/tex]

### Combine All Expanded Terms

Now, add all the expanded terms:
[tex]\[ x^3 + y^3 + y^3 + z^3 + z^3 + x^3 = 2(x^3 + y^3 + z^3) \][/tex]

Given [tex]\( x^3 + y^3 + z^3 = 1 \)[/tex], substitute:
[tex]\[ 2(x^3 + y^3 + z^3) = 2 \cdot 1 = 2 \][/tex]

Thus, the combined exponent simplifies to [tex]\(2\)[/tex], yielding:
[tex]\[ a^{2} \][/tex]

### Conclusion

Therefore, we have proven that:
[tex]\[ \left( \frac{a^x}{a^{-y}} \right)^{x^2 - xy + y^2} \times \left( \frac{a^y}{a^{-z}} \right)^{y^2 - yz + z^2} \times \left( \frac{a^z}{a^{-x}} \right)^{z^2 - zx + x^2} = a^2 \][/tex]

This concludes the proof.