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If the matrix A=[02yzxy−zx−yz]A = \begin{bmatrix} 0 & 2y & z \\ x & y & -z \\ x & -y & z \end{bmatrix} satisfies the equation ATA=I3A^T A = I_3, then x2+y2+z2x^2 + y^2 + z^2 is :

Solution

✅ Correct Option: 2

ATA=IA^T A = I implies columns of AA are orthonormal. Column norms: 0+x2+x2=2x2=10 + x^2 + x^2 = 2x^2 = 1, 4y2+y2+y2=6y2=14y^2 + y^2 + y^2 = 6y^2 = 1, z2+z2+z2=3z2=1z^2 + z^2 + z^2 = 3z^2 = 1. So x2=12x^2 = \frac{1}{2}, y2=16y^2 = \frac{1}{6}, z2=13z^2 = \frac{1}{3}. Sum =3+1+26=1= \frac{3+1+2}{6} = 1.

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