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if a gt b gt c and the system of equatio...

if `a gt b gt c` and the system of equations `ax + by + cz = 0, bx + cy + az 0 and cx + ay + bz = 0` has a non-trivial solution, then the quadratic equation `ax^(2) + bx + c =0` has

A

at least one positive root

B

roots opposite in sign

C

positive roots

D

imaginary roots

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To solve the problem step by step, we will analyze the given system of equations and the conditions provided. ### Step 1: Write down the system of equations We have the following system of equations: 1. \( ax + by + cz = 0 \) 2. \( bx + cy + az = 0 \) 3. \( cx + ay + bz = 0 \) ### Step 2: Formulate the determinant To find the condition for a non-trivial solution, we need to calculate the determinant of the coefficients of the variables \(x\), \(y\), and \(z\): \[ \Delta = \begin{vmatrix} a & b & c \\ b & c & a \\ c & a & b \end{vmatrix} \] ### Step 3: Calculate the determinant Using the determinant formula for a \(3 \times 3\) matrix, we expand it: \[ \Delta = a \begin{vmatrix} c & a \\ a & b \end{vmatrix} - b \begin{vmatrix} b & a \\ c & b \end{vmatrix} + c \begin{vmatrix} b & c \\ c & a \end{vmatrix} \] Calculating the minors: 1. \( \begin{vmatrix} c & a \\ a & b \end{vmatrix} = cb - a^2 \) 2. \( \begin{vmatrix} b & a \\ c & b \end{vmatrix} = bb - ac = b^2 - ac \) 3. \( \begin{vmatrix} b & c \\ c & a \end{vmatrix} = ba - c^2 \) Substituting these back into the determinant: \[ \Delta = a(cb - a^2) - b(b^2 - ac) + c(ba - c^2) \] \[ = acb - a^3 - b^3 + abc + abc - c^3 \] \[ = -a^3 + b^3 + c^3 - 3abc \] ### Step 4: Set the determinant to zero for non-trivial solutions For the system to have a non-trivial solution, we set the determinant to zero: \[ -a^3 + b^3 + c^3 - 3abc = 0 \] This can be rearranged to: \[ a^3 + b^3 + c^3 - 3abc = 0 \] ### Step 5: Analyze the implications From the identity \(a^3 + b^3 + c^3 - 3abc = (a+b+c)(a^2 + b^2 + c^2 - ab - ac - bc)\), we can conclude that either: 1. \( a + b + c = 0 \) 2. \( a^2 + b^2 + c^2 - ab - ac - bc = 0 \) ### Step 6: Determine the case Given the condition \(a > b > c\), the second case cannot hold (as it would imply \(a = b = c\)). Therefore, we must have: \[ a + b + c = 0 \] ### Step 7: Substitute into the quadratic equation Now, we consider the quadratic equation: \[ ax^2 + bx + c = 0 \] Substituting \(x = 1\): \[ f(1) = a(1)^2 + b(1) + c = a + b + c = 0 \] ### Conclusion Since \(x = 1\) is a root of the quadratic equation, we conclude that the quadratic equation \(ax^2 + bx + c = 0\) has at least one root, which is \(x = 1\). ### Final Answer Thus, the quadratic equation \(ax^2 + bx + c = 0\) has at least one positive root. ---

To solve the problem step by step, we will analyze the given system of equations and the conditions provided. ### Step 1: Write down the system of equations We have the following system of equations: 1. \( ax + by + cz = 0 \) 2. \( bx + cy + az = 0 \) 3. \( cx + ay + bz = 0 \) ...
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OBJECTIVE RD SHARMA ENGLISH-DETERMINANTS-Chapter Test
  1. if a gt b gt c and the system of equations ax + by + cz = 0, bx + cy +...

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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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