The curve C has equation $y = x(5 - x)$ and the line L has equation $2y = 5x + 4$
(a) Use algebra to show that C and L do not intersect - Edexcel - A-Level Maths Pure - Question 7 - 2012 - Paper 1
Question 7
The curve C has equation $y = x(5 - x)$ and the line L has equation $2y = 5x + 4$
(a) Use algebra to show that C and L do not intersect.
(b) In the space on page 1... show full transcript
Worked Solution & Example Answer:The curve C has equation $y = x(5 - x)$ and the line L has equation $2y = 5x + 4$
(a) Use algebra to show that C and L do not intersect - Edexcel - A-Level Maths Pure - Question 7 - 2012 - Paper 1
Step 1
In the space on page 11, sketch C and L on the same diagram, showing the coordinates of the points at which C and L meet the axes.
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Answer
In the sketch, we will display both curves:
Curve C:
It has a parabolic shape opening downwards.
It passes through the points (0, 0) and (5, 0).
The y-intercept is at (0, 0), and the vertex can be found at (2.5, 6.25) using the vertex formula.
Line L:
It is a straight line with a positive gradient.
It intersects the y-axis at (0, 2).
The x-intercept can be found by setting y=0, leading to 5x+4=0⇒x=−54. This is approximately (-0.8, 0).
Both curves should be clearly labeled, including their respective axis intersection points.