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2 votes
X+y+z=0
x^2+y^2+z^2=1
x^4+y^4+z^4=?

User Chakrava
by
4.3k points

1 Answer

6 votes

x^4+y^4+z^4= 0.5 is the answer.

Explanation:

we know that given,

x+y+z=0

x^2+y^2+z^2=1

x^4+y^4+z^4=?

2 (xy+yz+zx) = (x+y+z)^2 - (x^2+y^2+z^2) = -1

(xy + yz+ zx) = -1 ÷ 2

We also know the formula,

6xyz = (x+y+z)^3- 3 (x+y+z) (x^2+y^2+z^2) + 2(x^3+y^3+z^3) = 1

xyz = 1 ÷ 6

x^4+y^4+z^4 = (x^2+y^2+z^2)^2 - 2(x^2y^2+y^2z^2+z^2x^2)

= (x^2+y^2+z^2)^2 - 2 ((xy+yz+zx)^2 - 2xyz (x+y+z))

= 1 - 2( 1÷4 ) - 2( 1÷6 ) (0)

= 0.5

User Danyelle
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4.8k points