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Given the equation: $x^2 - 2x + 6 = 0$ 2.1.1 Determine the numerical value of the discriminant - NSC Technical Mathematics - Question 2 - 2022 - Paper 1

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Given the equation: $x^2 - 2x + 6 = 0$ 2.1.1 Determine the numerical value of the discriminant. 2.1.2 Hence, describe the nature of the roots of the equation. ... show full transcript

Worked Solution & Example Answer:Given the equation: $x^2 - 2x + 6 = 0$ 2.1.1 Determine the numerical value of the discriminant - NSC Technical Mathematics - Question 2 - 2022 - Paper 1

Step 1

Determine the numerical value of the discriminant.

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Answer

To find the discriminant riangle riangle of the quadratic equation, we use the formula:

riangle=b24ac riangle = b^2 - 4ac

For the given equation x22x+6=0x^2 - 2x + 6 = 0, we can identify the coefficients as follows:

  • a=1a = 1
  • b=2b = -2
  • c=6c = 6

Substituting these values into the discriminant formula:

riangle=(2)24(1)(6) riangle = (-2)^2 - 4(1)(6) riangle=424 riangle = 4 - 24 riangle=20 riangle = -20

Thus, the numerical value of the discriminant is 20-20.

Step 2

Hence, describe the nature of the roots of the equation.

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Answer

Since the discriminant riangle=20 riangle = -20 is less than zero, it indicates that the roots of the equation are non-real or imaginary roots. This means that the quadratic equation does not intersect the x-axis.

Step 3

Determine the numerical value of $k$ for which the equation $x^2 + 2x + k = 0$ will have real roots.

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Answer

To find the value of kk that allows the quadratic equation to have real roots, again we calculate the discriminant:

riangle=b24ac riangle = b^2 - 4ac

For this equation, we have:

  • a=1a = 1
  • b=2b = 2
  • c=kc = k

Substituting these values, we get:

riangle=(2)24(1)(k) riangle = (2)^2 - 4(1)(k) riangle=44k riangle = 4 - 4k

For the equation to have real roots, we require riangleeq0 riangle eq 0, which leads to:

44k04 - 4k \geq 0 4\eq4k4 \eq 4k k\eq1k \eq 1

Thus, the numerical value of kk must satisfy k\eq1k \eq 1 to ensure that the equation has real roots.

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