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If a, b and c are non-zero real numbers ...

If a, b and c are non-zero real numbers and `|(1+a,1,1),(1,1+b,1),(1,1,1+c)|=0`, then what is the value of `(1)/(a) + (1)/(b) + (1)/(c)` ?

A

2

B

1

C

-1

D

0

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to evaluate the determinant and find the value of \(\frac{1}{a} + \frac{1}{b} + \frac{1}{c}\) given that the determinant equals zero. ### Step 1: Write the determinant We have the determinant: \[ D = \begin{vmatrix} 1 + a & 1 & 1 \\ 1 & 1 + b & 1 \\ 1 & 1 & 1 + c \end{vmatrix} \] ### Step 2: Apply row operations We can simplify the determinant by applying the operation \(C_2 - C_1\) and \(C_3 - C_1\). This gives us: \[ D = \begin{vmatrix} 1 + a & 0 & 0 \\ 1 & b & 0 \\ 1 & 0 & c \end{vmatrix} \] ### Step 3: Evaluate the determinant Now we can evaluate the determinant: \[ D = (1 + a) \begin{vmatrix} b & 0 \\ 0 & c \end{vmatrix} - 0 + 0 \] Calculating the 2x2 determinant: \[ D = (1 + a)(bc) \] ### Step 4: Set the determinant to zero Since we are given that the determinant equals zero: \[ (1 + a)(bc) = 0 \] Since \(a\), \(b\), and \(c\) are non-zero, we conclude: \[ 1 + a = 0 \implies a = -1 \] ### Step 5: Find the relationship for \(b\) and \(c\) Similarly, we can apply the same reasoning for \(b\) and \(c\): \[ 1 + b = 0 \implies b = -1 \] \[ 1 + c = 0 \implies c = -1 \] ### Step 6: Calculate \(\frac{1}{a} + \frac{1}{b} + \frac{1}{c}\) Now we can find: \[ \frac{1}{a} + \frac{1}{b} + \frac{1}{c} = \frac{1}{-1} + \frac{1}{-1} + \frac{1}{-1} = -1 - 1 - 1 = -3 \] ### Final Answer Thus, the value of \(\frac{1}{a} + \frac{1}{b} + \frac{1}{c}\) is: \[ \boxed{-3} \]
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PUNEET DOGRA-DETERMINANTS -PREV YEAR QUESTIONS
  1. If a, b and c are non-zero real numbers and |(1+a,1,1),(1,1+b,1),(1,1,...

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  2. What is the value of determinant |(1!,2!,3!),(2!,3!,4!),(3!,4!,5!)| ?

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  3. What are the values of x that satisfy equation |(x,0,2),(2x,2,1),(1,1,...

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  4. The factor of the determinant |(x+a,b,c),(a,x+b,c),(a,b,x+c)| is

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  5. If |(x,-3i,1),(y,1,i),(0,2i,-i)|=6+11i. then what are the value of x a...

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  6. A is a square matrix of order 3 such that its determinant is 4. What i...

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  7. If A is a square matrix of order n gt 1, then which one of the followi...

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  8. Let A and B be (3 xx 3) matrices with det A = 4 and det B = 3 What i...

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  9. Let A and B be (3 xx 3) matrices with det A = 4 and det B = 3 What i...

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  10. If in a triangle ABC, |{:(1, sin A ,sin^(2)A),(1,sin B , sin^(2)B),(1,...

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  11. Find the values of x,y,z if the matrix A=[(0,3y,z),(x,y,-z),(x,-y,z)] ...

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  12. If u, v and w (all positive) are the pth, qth, and rth terms of a GP, ...

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  13. If a + b + c = 0, then one of the solution of |(a-x,c,b),(c,b-x,a),(b,...

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  14. Which one of the following factors does the expansions of the determin...

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  15. The system of equation 2x + y - 3z = 5 3x - 2y + 2z = 5 5x - 3y ...

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  16. The value of the determinants |("cos"^(2)(theta)/(2),"sin"^(2)(theta)/...

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  17. The system of equation kx + y + z = 1, x + ky + z = k and x + y + kz =...

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  18. If p + q + r = a + b + c = 0, then the determinant |(pa,qb,rc),(qc,ra,...

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  19. The value of the determinant : |(1-alpha,alpha-alpha^(2),alpha^(2)),(1...

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  20. If B is a non-singular matrix and A is a square matrix, then the value...

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  21. What is the value of the determinant ? |(1,1,1),(1,1+xyz,1),(1,1,1+x...

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