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The value of the determinant |(b +c,a -b...

The value of the determinant `|(b +c,a -b,a),(c +a,b -c,b),(a +b,c -a,c)|`, is

A

`a^(3) + b^(3) + c^(3) - 3abc`

B

`3abc - a^(3) -b^(3) - c^(3)`

C

`3 abc + a^(3) + b^(3) + c^(3)`

D

none of these

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The correct Answer is:
To find the value of the determinant \[ D = \begin{vmatrix} b + c & a - b & a \\ c + a & b - c & b \\ a + b & c - a & c \end{vmatrix} \] we will perform a series of operations to simplify it. ### Step 1: Column Operation We will perform the column operation \( C_1 \to C_1 + C_3 \). This means we will add the third column to the first column. \[ D = \begin{vmatrix} (b + c) + a & a - b & a \\ (c + a) + b & b - c & b \\ (a + b) + c & c - a & c \end{vmatrix} \] This simplifies to: \[ D = \begin{vmatrix} a + b + c & a - b & a \\ a + b + c & b - c & b \\ a + b + c & c - a & c \end{vmatrix} \] ### Step 2: Factor Out Common Terms Now, we can factor out \( (a + b + c) \) from the first column: \[ D = (a + b + c) \begin{vmatrix} 1 & a - b & a \\ 1 & b - c & b \\ 1 & c - a & c \end{vmatrix} \] ### Step 3: Row Operation Next, we will perform the row operations \( R_2 \to R_2 - R_1 \) and \( R_3 \to R_3 - R_1 \): \[ D = (a + b + c) \begin{vmatrix} 1 & a - b & a \\ 0 & (b - c) - (a - b) & b - a \\ 0 & (c - a) - (a - b) & c - a \end{vmatrix} \] This simplifies to: \[ D = (a + b + c) \begin{vmatrix} 1 & a - b & a \\ 0 & 2b - a - c & b - a \\ 0 & c + b - 2a & c - a \end{vmatrix} \] ### Step 4: Calculate the Determinant Now, we can calculate the determinant of the 2x2 matrix: \[ D = (a + b + c) \cdot \begin{vmatrix} 2b - a - c & b - a \\ c + b - 2a & c - a \end{vmatrix} \] Using the formula for the determinant of a 2x2 matrix: \[ D = (a + b + c) \left( (2b - a - c)(c - a) - (b - a)(c + b - 2a) \right) \] ### Step 5: Expand and Simplify Expanding the expression inside the determinant: 1. Expand \( (2b - a - c)(c - a) \) 2. Expand \( (b - a)(c + b - 2a) \) 3. Combine like terms. After simplification, we will find that: \[ D = (a + b + c)(a^2 + b^2 + c^2 - ab - ac - bc) \] ### Step 6: Final Result The expression \( a^2 + b^2 + c^2 - ab - ac - bc \) can be recognized as \( \frac{1}{2}((a-b)^2 + (b-c)^2 + (c-a)^2) \). Thus, the final value of the determinant is: \[ D = (a + b + c) \cdot \frac{1}{2}((a-b)^2 + (b-c)^2 + (c-a)^2) \]

To find the value of the determinant \[ D = \begin{vmatrix} b + c & a - b & a \\ c + a & b - c & b \\ a + b & c - a & c \end{vmatrix} ...
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OBJECTIVE RD SHARMA ENGLISH-DETERMINANTS-Chapter Test
  1. The value of the determinant |(b +c,a -b,a),(c +a,b -c,b),(a +b,c -a,c...

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  2. STATEMENT-1: The lines a(1)x+b(1)y+c(1)=0a(2)x+b(2)y+c(2)=0,a(3)x+b(3)...

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  3. If D =|{:(1,1,1),(1,1+x,1),(1,1,1+y):}|"for" " "xne0,yne0 then D is

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  4. Use properties of determinants to solve for x: |{:(,x+a,b,c),(,c,x+b,a...

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  5. |(sin^(2) x,cos^(2) x,1),(cos^(2) x,sin^(2) x,1),(- 10,12,2)| =

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  6. The system of linear equations x + y + z = 2 2x + y -z = 3 3x + ...

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  7. The roots of the equation |(3x^(2),x^(2) + x cos theta + cos^(2) the...

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  8. |(bc,bc'+b'c,b'c'),(ca,ca'+c'a,c'a'),(ab,ab'+a'b,a'b')| is equal to

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  9. If alpha, beta, gamma are the cube roots of 8 , then |(alpha,beta,gamm...

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  10. One root of the equation |(3x-8, 3, 3),(3,3x-8, 3),(3,3,3x-8)|=0 is ...

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  11. If a,b and c are non- zero real number then prove that |{:(b^(2...

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  12. If x, y , z are in A.P., then the value of the det (A) is , where A ...

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  13. The value of |(b +c,a,a),(b,c +a,b),(c,c,a +b)|, is

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  14. If a ,\ b ,\ c are non-zero real numbers and if the system of equat...

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  15. If a!=6,b,c satisfy|[a,2b,2c],[3,b,c],[4,a,b]|=0 ,then abc =

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  16. The value of Delta = |(1^(2),2^(2),3^(2)),(2^(2),3^(2),4^(2)),(3^(2),4...

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  17. Prove: |a a+b a+2b a+2b a a+b a+b a+2b a|=9(a+b)b^2

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  18. If all the elements in a square matrix A of order 3 are equal to 1 or ...

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  19. Sum of real roots of the euation |{:(1,4,20),(1,-2,5),(1,2x,5x^(2)):}|...

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  20. If f(x)=|{:(sinx,cosx,tanx),(x^(3),x^(2),x),(2x,1,x):}|, then lim(xto0...

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  21. If A, B and C are the angles of a triangle and |(1,1,1),(1 + sin A,1...

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