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If the expression |{:(x^2+x+3,1,4),(2x^4...

If the expression `|{:(x^2+x+3,1,4),(2x^4+x^3+2x+1,2,3),(x^2+x,1,1):}|` is equal to `ax^4+bx^3+cx^2+dx+e`, then the value of e is equal to

A

zero

B

1

C

2

D

none of these

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The correct Answer is:
To solve the determinant given in the expression \( |{:(x^2+x+3,1,4),(2x^4+x^3+2x+1,2,3),(x^2+x,1,1):}| \) and find the value of \( e \) in the polynomial \( ax^4 + bx^3 + cx^2 + dx + e \), we can follow these steps: ### Step 1: Write the Determinant We need to evaluate the determinant: \[ D = \begin{vmatrix} x^2 + x + 3 & 1 & 4 \\ 2x^4 + x^3 + 2x + 1 & 2 & 3 \\ x^2 + x & 1 & 1 \end{vmatrix} \] ### Step 2: Expand the Determinant We can expand the determinant using the first row: \[ D = (x^2 + x + 3) \begin{vmatrix} 2 & 3 \\ 1 & 1 \end{vmatrix} - 1 \begin{vmatrix} 2x^4 + x^3 + 2x + 1 & 3 \\ x^2 + x & 1 \end{vmatrix} + 4 \begin{vmatrix} 2x^4 + x^3 + 2x + 1 & 2 \\ x^2 + x & 1 \end{vmatrix} \] ### Step 3: Calculate the 2x2 Determinants 1. For the first determinant: \[ \begin{vmatrix} 2 & 3 \\ 1 & 1 \end{vmatrix} = (2 \cdot 1) - (3 \cdot 1) = 2 - 3 = -1 \] 2. For the second determinant: \[ \begin{vmatrix} 2x^4 + x^3 + 2x + 1 & 3 \\ x^2 + x & 1 \end{vmatrix} = (2x^4 + x^3 + 2x + 1) \cdot 1 - (3 \cdot (x^2 + x)) = 2x^4 + x^3 + 2x + 1 - 3x^2 - 3x = 2x^4 + x^3 - 3x^2 - x + 1 \] 3. For the third determinant: \[ \begin{vmatrix} 2x^4 + x^3 + 2x + 1 & 2 \\ x^2 + x & 1 \end{vmatrix} = (2x^4 + x^3 + 2x + 1) \cdot 1 - (2 \cdot (x^2 + x)) = 2x^4 + x^3 + 2x + 1 - 2x^2 - 2x = 2x^4 + x^3 - 2x^2 + 1 \] ### Step 4: Substitute Back into the Determinant Now substitute these back into the determinant: \[ D = (x^2 + x + 3)(-1) - 1(2x^4 + x^3 - 3x^2 - x + 1) + 4(2x^4 + x^3 - 2x^2 + 1) \] \[ D = -(x^2 + x + 3) - (2x^4 + x^3 - 3x^2 - x + 1) + 4(2x^4 + x^3 - 2x^2 + 1) \] ### Step 5: Simplify the Expression Now, simplify the expression: \[ D = -x^2 - x - 3 - 2x^4 - x^3 + 3x^2 + x - 1 + 8x^4 + 4x^3 - 8x^2 + 4 \] Combine like terms: \[ D = (8x^4 - 2x^4) + (-x^3 + 4x^3) + (-x^2 + 3x^2 - 8x^2) + (-3 - 1 + 4) \] \[ D = 6x^4 + 3x^3 - 6x^2 + 0 \] ### Step 6: Identify Coefficients From the expression \( D = 6x^4 + 3x^3 - 6x^2 + 0 \), we can see that: - \( a = 6 \) - \( b = 3 \) - \( c = -6 \) - \( d = 0 \) - \( e = 0 \) ### Conclusion Thus, the value of \( e \) is: \[ \boxed{0} \]
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FIITJEE-DETERMINANT-ASSIGNMENT PROBLEMS (OBJECTIVE) LEVEL-I
  1. If f(x) =|{:(cosx,1,0),(1,2 cosx,1),(0,1,2 cosx):}|, "then" |overset(p...

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  2. If f(x)=|{:(x,cosx,e^(x^2)),(1,2 cosx,1),(0,1,2 cosx):}| then the valu...

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  3. If the expression |{:(x^2+x+3,1,4),(2x^4+x^3+2x+1,2,3),(x^2+x,1,1):}| ...

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  4. The determinant Delta=|{:(a,b,aalpha+c),(b,c,balpha+c),(aalpha+b,balph...

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  5. If alpha,beta & gamma are the roots the equations x^(3)+px+q=0 then th...

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

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  7. The determinant Delta =|(a^2(1+x),ab,ac),(ab,b^2(1+x),bc), (ac,bc,c^2(...

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  8. If alpha , beta and gamma the roots of the equation x^2(px + q) = r(x...

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  9. If the system of equations x+a y=0,a z+y=0 and a x+z=0 has infinite so...

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  10. If A+B+C =pi , then the value of determinant |{:(sin^2A,cotA,1),(sin^2...

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  11. For A=a^2+b^2+c^2,B=ab+bc+ca,(a^3,b^3c^3-3abc)^2 is equal to

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  12. If A, B, C are angle of a triangle ABC, then the value of the determi...

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  13. If the expression |{:(x^2+x+3,1,4),(2x^4+x^3+2x+1,2,3),(x^2+x,1,1):}| ...

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  14. The sum of two non integral roots of |{:(x,2,5),(3,x,3),(5,4,x):}|=0 i...

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  15. |[1,1,1] , [(2^x+2^(-x))^2, (3^x+3^(-x))^2, (5^x+5^(-x))^2] , [(2^x-2^...

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  16. There are three points (a,x) ,(b,y) and (c,z) such that the straight l...

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  17. If |{:(overset(n-2)underset(k=0)sum1,n(n-1),n^2),(overset(n)underset(k...

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  18. Delta=|{:(1+a^2+a^4,1+ab+a^2b^2,1+ac+a^2c^2),(1+ab+a^2b^2,1+b^2+b^4,1+...

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  19. If A(x1, y1), B (x2, y2) and C (x3, y3) are the vertices of a DeltaABC...

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  20. The number of distinct real roots of |s in x cos x cos x cos x s in x ...

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