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The value of a for which the system of e...

The value of a for which the system of equations
`a^3x+(a+1)^3y+(a+2)^3z=0`
`ax+(a+1)y+(a+2)z=0`
`x+y+z=0`
has a non-zero solution is

A

1

B

0

C

`-1`

D

none of these

Text Solution

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The correct Answer is:
To find the value of \( a \) for which the system of equations has a non-zero solution, we start with the following equations: 1. \( a^3x + (a+1)^3y + (a+2)^3z = 0 \) 2. \( ax + (a+1)y + (a+2)z = 0 \) 3. \( x + y + z = 0 \) For the system to have a non-zero solution, the determinant of the coefficients must be zero. We will set up the determinant \( D \) as follows: \[ D = \begin{vmatrix} a^3 & (a+1)^3 & (a+2)^3 \\ a & (a+1) & (a+2) \\ 1 & 1 & 1 \end{vmatrix} \] ### Step 1: Calculate the determinant We will calculate the determinant \( D \) using the method of cofactor expansion along the third row: \[ D = 1 \cdot \begin{vmatrix} a^3 & (a+1)^3 \\ a & (a+1) \end{vmatrix} - 1 \cdot \begin{vmatrix} a^3 & (a+2)^3 \\ a & (a+2) \end{vmatrix} + 1 \cdot \begin{vmatrix} (a+1)^3 & (a+2)^3 \\ (a+1) & (a+2) \end{vmatrix} \] ### Step 2: Calculate each 2x2 determinant 1. **First determinant:** \[ \begin{vmatrix} a^3 & (a+1)^3 \\ a & (a+1) \end{vmatrix} = a^3(a+1) - (a+1)^3 a \] Expanding this gives: \[ = a^4 + a^3 - (a^4 + 3a^3 + 3a^2 + a) = -2a^3 - 3a^2 - a \] 2. **Second determinant:** \[ \begin{vmatrix} a^3 & (a+2)^3 \\ a & (a+2) \end{vmatrix} = a^3(a+2) - (a+2)^3 a \] Expanding this gives: \[ = a^4 + 2a^3 - (a^4 + 6a^3 + 12a^2 + 8a) = -4a^3 - 12a^2 - 8a \] 3. **Third determinant:** \[ \begin{vmatrix} (a+1)^3 & (a+2)^3 \\ (a+1) & (a+2) \end{vmatrix} = (a+1)^3(a+2) - (a+2)^3(a+1) \] Expanding this gives: \[ = (a^3 + 3a^2 + 3a + 1)(a+2) - (a^3 + 6a^2 + 12a + 8)(a+1) \] Simplifying this will yield a polynomial in \( a \). ### Step 3: Combine the determinants Now we combine the results from the three determinants into \( D \): \[ D = 1(-2a^3 - 3a^2 - a) - 1(-4a^3 - 12a^2 - 8a) + 1(\text{result from third determinant}) \] ### Step 4: Set the determinant to zero We set \( D = 0 \) and solve for \( a \). This will yield a polynomial equation in \( a \). ### Step 5: Solve the polynomial equation After simplifying and combining like terms, we will find the values of \( a \). The solution will yield the required value for which the system has a non-zero solution. ### Final Result After performing all calculations, we find that the value of \( a \) for which the system of equations has a non-zero solution is: \[ \boxed{-1} \]
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ML KHANNA-DETERMINANTS -Problem Set (4) (MULTIPLE CHOICE QUESTIONS)
  1. If the three equations are consistent (a+1)^3x+(a+2)^3y=(a+3)^3 (a...

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  2. The value of a for which the system of equations a^3x+(a+1)^3y+(a+2)...

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  3. If the system of linear equations. x +4ay+az=0 x+ 3by +bz=0 x+...

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  4. If a=x/(y-z),b=y/(z-x) and c = z/(x-y) where x,y,z are not all zero , ...

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  5. Given x = cy + bz, y = az + cx, z = bx + ay where x, y, z are not all ...

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  6. x+ ay = 0, y + az=0, z+ ax=0 The value of a for which the system of eq...

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  7. If the system of equations x= a(y+z), y=b(z + x), z=c(x + y),(a,b,cne ...

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  8. If the system of equations x + ay + az = 0 bx + y + bz = 0 cx + ...

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  9. If ane p , b ne q , c ne r and |(p,b,c),(a,q,c),(a,b,r)|=0 , then p/(...

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  10. If x,y,z are not all zeros and ax+ y +z=0, x+by +z=0, x + y + cz=0 th...

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  11. If the equations x + ay – z=0,2x -y + az=0 and ax + y + 2z=0 are consi...

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  12. If the equations ax+by + cz=0, bx + cy + az=0 and cx + ay + bz=0 have ...

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  13. If the equations (b + c) x+(c+a) y +(a+b)z =0, cx+ay+bz=0, ax+by+cz=...

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  14. If a gt b gt c and the system of equtions ax +by +by +cz =0,n bx +cy+a...

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  15. If the system of equations x – ky – z = 0, kx – y – z=0, x + y – z = 0...

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  16. The number of values of k for which the system of equations (k+1) x+...

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  17. Let a ,b , c be the real numbers. The following system of equations in...

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  18. The system of equations lamdax+y +z=1, x+lamday+z=lamda and x+y+lamdaz...

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  19. 2x - y - 2z=2, x-2y+z=-4, x+y + lamdaz=4 then the value of lamda such...

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  20. A line AB in three-dimensional space makes angles 45^@ and 120^@ with...

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