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For the quadratic polynomial f (x) =4x ^...

For the quadratic polynomial `f (x) =4x ^(2)-8ax+a.` the statements (s) which hold good is/are:

A

There is only one integral 'a' for which f (x) is non- negative `AA x in R`

B

For `a lt 0,` the number zero lies between the zeroes of the polynomial

C

`f (x) =0` has two distinct solutions in `(0,1) ` for `a in ((1)/(7), (4)/(7))`

D

The minimum value of `f (x)` for minimum value of a for which f (x) is non-negative `AA x in R` is 0

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The correct Answer is:
To solve the problem, we need to analyze the quadratic polynomial \( f(x) = 4x^2 - 8ax + a \) and determine which statements hold true regarding the values of \( a \) for which the function is non-negative. ### Step 1: Understanding Non-negativity of the Quadratic Polynomial For the quadratic polynomial \( f(x) \) to be non-negative for all \( x \in \mathbb{R} \), the discriminant must be less than or equal to zero. The discriminant \( D \) for a quadratic polynomial \( ax^2 + bx + c \) is given by: \[ D = b^2 - 4ac \] In our case, \( a = 4 \), \( b = -8a \), and \( c = a \). Thus, the discriminant becomes: \[ D = (-8a)^2 - 4 \cdot 4 \cdot a = 64a^2 - 16a \] ### Step 2: Setting the Discriminant Less Than or Equal to Zero To ensure \( f(x) \) is non-negative, we set the discriminant less than or equal to zero: \[ 64a^2 - 16a \leq 0 \] ### Step 3: Factoring the Discriminant Factoring out \( 16a \): \[ 16a(4a - 1) \leq 0 \] ### Step 4: Finding Critical Points The critical points are found by setting each factor to zero: 1. \( 16a = 0 \) gives \( a = 0 \) 2. \( 4a - 1 = 0 \) gives \( a = \frac{1}{4} \) ### Step 5: Analyzing the Sign of the Expression We analyze the intervals determined by the critical points \( a = 0 \) and \( a = \frac{1}{4} \): - For \( a < 0 \): \( 16a < 0 \) and \( 4a - 1 < 0 \) → product is positive. - For \( 0 < a < \frac{1}{4} \): \( 16a > 0 \) and \( 4a - 1 < 0 \) → product is negative. - For \( a = 0 \): \( 16a(4a - 1) = 0 \). - For \( a = \frac{1}{4} \): \( 16a(4a - 1) = 0 \). - For \( a > \frac{1}{4} \): \( 16a > 0 \) and \( 4a - 1 > 0 \) → product is positive. Thus, the expression \( 16a(4a - 1) \leq 0 \) holds for: \[ a \in [0, \frac{1}{4}] \] ### Step 6: Identifying Integral Values The integral values of \( a \) in the interval \( [0, \frac{1}{4}] \) are only \( 0 \). Thus, there is only one integral value for which \( f(x) \) is non-negative. ### Step 7: Analyzing the Statements 1. **Statement 1**: There is only one integral value \( a \) for which \( f(x) \) is non-negative. **(True)** 2. **Statement 2**: If \( a < 0 \), then \( 0 \) lies between the roots of the polynomial. **(True)** 3. **Statement 3**: If \( f(x) = 0 \), then \( a \) is between \( \frac{1}{7} \) and \( \frac{4}{7} \). **(False)** 4. **Statement 4**: The minimum value of \( a \) for which \( f(x) \) is non-negative is \( 0 \). **(True)** ### Conclusion The correct statements are 1, 2, and 4.
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VK JAISWAL-QUADRATIC EQUATIONS -EXERCISE (ONE OR MORE THAN ONE ANSWER IS/ARE CORRECT)
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  2. If a,b,c are rational numbers (a gt b gt c gt 0) and quadratic equatio...

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  3. For the quadratic polynomial f (x) =4x ^(2)-8ax+a. the statements (s) ...

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  4. Given a,b, c are three distinct real numbers satisfying the inequality...

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  5. Let f (x) =x ^(2) -4x +c AA x in R, where c is a real constant, then w...

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  6. If 0 lt a lt b lt c and the roots alpha, beta of the equation ax ^(2)...

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  7. If satisfies |x-1| + |x-2|+|x-3|gt6, then :

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  8. If both roots of the quadratic equation ax ^(2)+x+b-a =0 are non real ...

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  9. If a,b are two numbers such that a ^(2) +b^(2) =7 and a ^(3) + b^(3) =...

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  10. The number of non-negative integral ordered pair (s) (x,y) for which ...

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  11. If alpha, beta, gamma and delta are the roots of the equation x ^(4) -...

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  12. The value of 'k' for which roots of the equation 4x^2-2x+k=0 are comp...

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  13. If a,b,c in R, then for which of the following graphs of the quadrati...

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  14. If a x^2+b x+c=0,a ,b ,c in R has no real zeros, and if c<o , then wh...

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  15. If alpha and beta are the roots of the equation ax ^(3) + bx + c=0,a,b...

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  16. The equation cos ^(2) x - sin x+lamda = 0, x in (0, pi//2) has roots t...

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  17. If the equation ln (x^(2) +5x ) -ln (x+a +3)=0 has exactly one solutio...

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  18. The number of non-negative integral ordered pair (s) (x,y) for which ...

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  19. If a lt 0, then the value of x satisfying x ^(2)-2a|x-a| -3a ^(2)=0 i...

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  20. If 0 lt a lt b lt c and the roots alpha, beta of the equation ax ^(2)...

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