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If |(p,q-y,r-z),(p-x,q,r-z),(p-x,q-y,r)|...

If `|(p,q-y,r-z),(p-x,q,r-z),(p-x,q-y,r)|` = 0 then the value of `p/x+q/y+r/z` is

A

0

B

1

C

2

D

4 pqr

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we start with the determinant given as: \[ D = \begin{vmatrix} p & q-y & r-z \\ p-x & q & r-z \\ p-x & q-y & r \end{vmatrix} \] We know that if the determinant \( D = 0 \), it indicates that the rows of the determinant are linearly dependent. ### Step 1: Row Operations We will perform row operations to simplify the determinant. Let's perform the following operations: - Replace \( R_2 \) with \( R_2 - R_1 \) - Replace \( R_3 \) with \( R_3 - R_1 \) After performing these operations, the determinant becomes: \[ D = \begin{vmatrix} p & q-y & r-z \\ (p-x) - p & q - (q-y) & (r-z) - (r-z) \\ (p-x) - p & (q-y) - (q-y) & r - (r-z) \end{vmatrix} \] This simplifies to: \[ D = \begin{vmatrix} p & q-y & r-z \\ -x & y & 0 \\ -x & 0 & z \end{vmatrix} \] ### Step 2: Expanding the Determinant Now we can expand the determinant using the first row: \[ D = p \begin{vmatrix} y & 0 \\ 0 & z \end{vmatrix} - (q-y) \begin{vmatrix} -x & 0 \\ -x & z \end{vmatrix} + (r-z) \begin{vmatrix} -x & y \\ -x & 0 \end{vmatrix} \] Calculating the 2x2 determinants: 1. \( \begin{vmatrix} y & 0 \\ 0 & z \end{vmatrix} = yz \) 2. \( \begin{vmatrix} -x & 0 \\ -x & z \end{vmatrix} = -xz \) 3. \( \begin{vmatrix} -x & y \\ -x & 0 \end{vmatrix} = xy \) Substituting these back into the determinant gives: \[ D = p(yz) - (q-y)(-xz) + (r-z)(xy) \] This simplifies to: \[ D = pyz + (q-y)xz + (r-z)xy \] ### Step 3: Setting the Determinant to Zero Since we know \( D = 0 \): \[ pyz + (q-y)xz + (r-z)xy = 0 \] ### Step 4: Rearranging the Equation Rearranging the equation gives: \[ pyz + qxz - yxz + rxy - zxy = 0 \] Combining like terms: \[ pyz + qxz + rxy - (yxz + zxy) = 0 \] ### Step 5: Dividing by xyz To isolate the terms, we divide the entire equation by \( xyz \): \[ \frac{p}{x} + \frac{q}{y} + \frac{r}{z} - 1 = 0 \] Thus, we have: \[ \frac{p}{x} + \frac{q}{y} + \frac{r}{z} = 1 \] ### Final Answer The value of \( \frac{p}{x} + \frac{q}{y} + \frac{r}{z} \) is: \[ \boxed{1} \]
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ML KHANNA-DETERMINANTS -Self Assessment Test
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  2. If a != b != c, are value of x which satisfies the equation |(0,x -a...

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  3. |(b+c,a,a),(b,c+a,b),(c,c,a+b)|=

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  4. |(1,1,1),(a,b,c),(a^3,b^3,c^3)|=

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  5. |(1/a,a^2,bc),(1/b,b^2,ca),(1/c,c^2,ab)|=

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  6. If x=-9 is a root of |(x,3,7),(2,x,2),(7,6,x)|=0 then other two roots ...

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  7. The solution of the equation |(x,2,-1),(2,5,x),(-1,2,x)| = 0 are

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  8. The roots of the equation |(0,x,16),(x,5,7),(0,9,x)| = 0 are

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  9. |(a+b,b+c,c+a),(b+c,c+a,a+b),(c+a,a+b,b+c)|=k|(a,b,c),(b,c,a),(c,a,b)|...

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  10. A root of the equation |(3-x,-6,3),(-6,3-x,3),(3,3,-6-x)| = 0

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  11. If |(-a^2,ab,ac),(ab,-b^2,bc),(ac,bc,-c^2)|=ka^2b^2c^2 , then k =

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  12. If omega!=1 is a cube root of unity and Delta=|(x+omega^(2),omega,1)...

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  13. |((a^x+a^(-x))^2,(a^x-a^(-x))^(2),1),((b^x+b^(-x))^2,(b^x-b^(-x))^(2),...

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  14. The number of values of k which the linear equations 4x+ky+2z=0 kx...

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  15. The value of k for which the set of equationsx + ky + 3z=0, 3x + ky – ...

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  17. The system of equations x + y + z=2, 3x – y +2z=6 and 3x + y +z=-18 ha...

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  18. The system of equations x+y+z=6, x+2y + 3z= 10, x+2y + lamdaz=mu has n...

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  19. The system of linear equations x1 + 2x2 + x3 = 3, 2x1 + 3x2 + x3 = 3...

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  20. Let a,b,c be such that b(a+c) ne 0 . If |(a,a+1,a-1),(-b,b+1,b-1),(c...

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