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If x+y+z=0=a+b+c, then |{:(xa,yb,zc),(yc...

If x+y+z=0=a+b+c, then `|{:(xa,yb,zc),(yc,za,xb),(zb,xc,ya):}|=`

A

0

B

`xa+yb+zc`

C

1

D

None of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the determinant given the conditions \(x + y + z = 0\) and \(a + b + c = 0\), we will follow these steps: ### Step 1: Write the Determinant We start with the determinant given by: \[ D = \begin{vmatrix} xa & yb & zc \\ yc & za & xb \\ zb & xc & ya \end{vmatrix} \] ### Step 2: Apply the Determinant Properties We can expand the determinant using the first row. The determinant can be calculated as: \[ D = xa \begin{vmatrix} za & xb \\ xc & ya \end{vmatrix} - yb \begin{vmatrix} yc & xb \\ zb & ya \end{vmatrix} + zc \begin{vmatrix} yc & za \\ zb & xc \end{vmatrix} \] ### Step 3: Calculate Each 2x2 Determinant Calculating the first 2x2 determinant: \[ \begin{vmatrix} za & xb \\ xc & ya \end{vmatrix} = (za)(ya) - (xb)(xc) = zay - bxy \] Calculating the second 2x2 determinant: \[ \begin{vmatrix} yc & xb \\ zb & ya \end{vmatrix} = (yc)(ya) - (xb)(zb) = yac - bzx \] Calculating the third 2x2 determinant: \[ \begin{vmatrix} yc & za \\ zb & xc \end{vmatrix} = (yc)(xc) - (za)(zb) = ycx - zab \] ### Step 4: Substitute Back into the Determinant Now substituting these back into the expression for \(D\): \[ D = xa(zay - bxy) - yb(yac - bzx) + zc(ycx - zab) \] ### Step 5: Expand and Simplify Expanding the terms: \[ D = xazay - xabxy - ybyac + ybbzx + zcycx - zcab \] ### Step 6: Factor Out Common Terms Notice that we can factor out \(xyz\) from the terms: \[ D = xyz(a^2 + b^2 + c^2 - ab - ac - bc) \] ### Step 7: Use the Given Conditions Since \(a + b + c = 0\), we can use the identity: \[ a^3 + b^3 + c^3 - 3abc = (a + b + c)(a^2 + b^2 + c^2 - ab - ac - bc) \] This means: \[ a^3 + b^3 + c^3 = 3abc \] ### Step 8: Conclude the Result Thus, we have: \[ D = xyz \cdot 0 = 0 \] ### Final Answer Therefore, the value of the determinant is: \[ \boxed{0} \]
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