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If the roots of the quadratic equation ...

If the roots of the quadratic equation `x^(2) +2x+k =0` are real, then

A

`k lt 0`

B

`k le 0`

C

`k lt 1`

D

`k le 1`

Text Solution

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The correct Answer is:
To determine the condition for the roots of the quadratic equation \(x^2 + 2x + k = 0\) to be real, we need to analyze the discriminant of the equation. The discriminant (\(D\)) is given by the formula: \[ D = b^2 - 4ac \] where \(a\), \(b\), and \(c\) are the coefficients of the quadratic equation \(ax^2 + bx + c = 0\). ### Step-by-step Solution: 1. **Identify the coefficients:** - From the equation \(x^2 + 2x + k = 0\), we have: - \(a = 1\) - \(b = 2\) - \(c = k\) 2. **Write the discriminant:** - Substitute the coefficients into the discriminant formula: \[ D = b^2 - 4ac = 2^2 - 4 \cdot 1 \cdot k \] 3. **Simplify the discriminant:** - Calculate \(b^2\): \[ D = 4 - 4k \] 4. **Set the discriminant condition for real roots:** - For the roots to be real, the discriminant must be greater than or equal to zero: \[ 4 - 4k \geq 0 \] 5. **Solve the inequality:** - Rearranging the inequality: \[ 4 \geq 4k \] - Divide both sides by 4: \[ 1 \geq k \] - This can also be written as: \[ k \leq 1 \] ### Conclusion: The condition for the roots of the quadratic equation \(x^2 + 2x + k = 0\) to be real is: \[ k \leq 1 \]
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