0580/43 May/Jun 2022, Question 8: Simultaneous Equations with a Curve
Cambridge IGCSE Mathematics 0580 · Paper 43 (Extended) · Calculator · 18 marks
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The question, in short
Given points A(−2, 7), B(1, −5), C(5, 4), work out midpoint, vector, length, and two line equations; then find intersections of y + 5x = 8 with y = 2x² + 6x − 13.
Summarised in our own words. Use the official paper for the exact wording and any diagrams.
Part (ai) · 2 marks
Find the midpoint coordinates of the line segment AB.
- 1Midpoint = ((−2 + 1)/2, (7 + (−5))/2)
- 2= (−0.5, 1)
Answer(−0.5, 1)
Part (aii) · 2 marks
Find the vector AC.
- 1→AC = (5 − (−2), 4 − 7)
- 2= column vector (7, −3)
Answercolumn vector (7, −3)
Part (aiii) · 2 marks
Find the magnitude of vector AC.
- 1|→AC| = √(7² + (−3)²) = √58
- 2= 7.615… ≈ 7.62
Answer7.62 or 7.615 to 7.616
Part (aiv) · 3 marks
Find the equation of line AB in the form y = mx + c.
- 1Gradient = (−5 − 7)/(1 − (−2)) = −12/3 = −4
- 27 = −4 × (−2) + c, so c = −1
- 3y = −4x − 1
Answery = −4x − 1
Part (av) · 3 marks
Find the equation, in y = mx + c form, of the line through C perpendicular to AB.
- 1Gradient of AB = (−5 − 7)/(1 − (−2)) = −12/3 = −4
- 2Perpendicular gradient = −1 ÷ (−4) = 1/4
- 3Substitute C(5, 4): 4 = 1/4 × 5 + c, so c = 11/4
- 4y = 1/4 x + 11/4
Answer1/4 x + 11/4
Part (b) · 6 marks
Find the coordinates of both intersection points P and Q of the line and the curve, showing all working.
- 1y = 8 − 5x, so 8 − 5x = 2x² + 6x − 13
- 22x² + 11x − 21 = 0
- 3(2x − 3)(x + 7) = 0, so x = 3/2 or x = −7
- 4x = 3/2: y = 8 − 7.5 = 1/2; x = −7: y = 8 + 35 = 43
- 5P(3/2, 1/2) and Q(−7, 43)
Answer(3/2, 1/2) and (−7, 43)
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Also searched as: 0580/43/M/J/22 · 0580_s22_qp_43 · 0580 s22 43 · question 8.
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