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The number of integral values of m for w...

The number of integral values of `m` for which the equation `(1+m^(2)) x^(2) - 2(1+3m)x+(1+8m) = 0`, has no real roots is

A

`3`

B

`1`

C

`2`

D

infinitely many

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The correct Answer is:
To determine the number of integral values of \( m \) for which the equation \[ (1+m^2)x^2 - 2(1+3m)x + (1+8m) = 0 \] has no real roots, we need to analyze the discriminant of the quadratic equation. The discriminant \( D \) must be less than 0 for the quadratic to have no real roots. ### Step 1: Identify coefficients The coefficients of the quadratic equation are: - \( a = 1 + m^2 \) - \( b = -2(1 + 3m) \) - \( c = 1 + 8m \) ### Step 2: Write the discriminant The discriminant \( D \) is given by the formula: \[ D = b^2 - 4ac \] Substituting the values of \( a \), \( b \), and \( c \): \[ D = [-2(1 + 3m)]^2 - 4(1 + m^2)(1 + 8m) \] ### Step 3: Simplify the discriminant Calculating \( b^2 \): \[ b^2 = 4(1 + 3m)^2 = 4(1 + 6m + 9m^2) = 4 + 24m + 36m^2 \] Now calculating \( 4ac \): \[ 4ac = 4(1 + m^2)(1 + 8m) = 4[(1 + 8m) + m^2(1 + 8m)] = 4(1 + 8m + m^2 + 8m^3) \] This expands to: \[ 4 + 32m + 4m^2 + 32m^3 \] ### Step 4: Set up the inequality Now substituting back into the discriminant: \[ D = (4 + 24m + 36m^2) - (4 + 32m + 4m^2 + 32m^3) \] This simplifies to: \[ D = 36m^2 - 4m^2 + 24m - 32m - 32m^3 = 32m^2 - 32m^3 - 8m \] ### Step 5: Factor the expression Factoring out \( -8m \): \[ D = -8m(4m^2 + 4m + 1) \] ### Step 6: Analyze the inequality For the quadratic \( 4m^2 + 4m + 1 \): This is always positive since its discriminant \( 4 - 16 = -12 < 0 \). Therefore, \( D < 0 \) when \( -8m < 0 \), which implies: \[ m > 0 \] ### Step 7: Count integral values Since \( m \) must be an integer greater than 0, the integral values of \( m \) are \( 1, 2, 3, \ldots \) which means there are infinitely many integral values of \( m \). ### Conclusion The number of integral values of \( m \) for which the equation has no real roots is: \[ \text{Infinitely many} \]

To determine the number of integral values of \( m \) for which the equation \[ (1+m^2)x^2 - 2(1+3m)x + (1+8m) = 0 \] has no real roots, we need to analyze the discriminant of the quadratic equation. The discriminant \( D \) must be less than 0 for the quadratic to have no real roots. ...
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