Given:
$$3x^2 + 2x + 2 = 0$$
2.1.1 Determine the numerical value of the discriminant (Δ) of the equation - NSC Technical Mathematics - Question 2 - 2020 - Paper 1
Question 2
Given:
$$3x^2 + 2x + 2 = 0$$
2.1.1 Determine the numerical value of the discriminant (Δ) of the equation.
2.1.2 Hence, describe the nature of the roots of the... show full transcript
Worked Solution & Example Answer:Given:
$$3x^2 + 2x + 2 = 0$$
2.1.1 Determine the numerical value of the discriminant (Δ) of the equation - NSC Technical Mathematics - Question 2 - 2020 - Paper 1
Step 1
2.1.1 Determine the numerical value of the discriminant (Δ) of the equation.
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Answer
To find the discriminant (Δ) of the quadratic equation 3x2+2x+2=0, we use the formula:
Δ=b2−4ac,
where a=3, b=2, and c=2.
Calculating:
Δ=(2)2−4(3)(2)Δ=4−24Δ=−20.
Step 2
2.1.2 Hence, describe the nature of the roots of the equation.
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Answer
Since the discriminant (Δ) is negative (Δ=−20), it indicates that the quadratic equation has no real roots. Therefore, the roots are non-real (or complex) and appear as conjugate pairs.
Step 3
2.2.1 Write the equation in the form ax² + bx + c = 0.
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Answer
Starting from the given equation:
x2−2px=3p2,
we can rearrange it to the standard quadratic form:
x2−2px−3p2=0,
where a=1, b=−2p, and c=−3p2.
Step 4
2.2.2 Hence, without solving the equation, show that the roots of the equation are rational.
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Answer
To determine whether the roots are rational, we calculate the discriminant (Δ) for the equation x2−2px−3p2=0:
Using the formula:
Δ=b2−4ac,
we have:
Δ=(−2p)2−4(1)(−3p2)Δ=4p2+12p2Δ=16p2.
Since 16p2 is a perfect square (as 16 and p2 are both non-negative), it implies that the roots of the equation will also be rational.