Skip to main contentSkip to solution

If A=[02−3y0−1zx0]A = \begin{bmatrix} 0 & 2 & -3 \\ y & 0 & -1 \\ z & x & 0 \end{bmatrix} is skew symmetric matrix, then x3+y3+z3−3xyzx^3 + y^3 + z^3 - 3xyz is equal to :

Solution

✅ Correct Option: 3

Skew-symmetric: aij=−ajia_{ij} = -a_{ji}.

a12=2,a21=y⇒y=−2a_{12} = 2, a_{21} = y \Rightarrow y = -2.

a13=−3,a31=z⇒z=3a_{13} = -3, a_{31} = z \Rightarrow z = 3.

a23=−1,a32=x⇒x=1a_{23} = -1, a_{32} = x \Rightarrow x = 1.

x3+y3+z3−3xyz=1−8+27−3(1)(−2)(3)=20+18=38x^3 + y^3 + z^3 - 3xyz = 1 - 8 + 27 - 3(1)(-2)(3) = 20 + 18 = 38.

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question