The curve C has equation $y = x(5 - x)$ and the line L has equation $2y = 5x + 4$ - Edexcel - A-Level Maths Pure - Question 5 - 2012 - Paper 1
Question 5
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 ... show full transcript
Worked Solution & Example Answer:The curve C has equation $y = x(5 - x)$ and the line L has equation $2y = 5x + 4$ - Edexcel - A-Level Maths Pure - Question 5 - 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
When sketching the graphs of C and L:
For Curve C (y=x(5−x)):
The x-intercepts are at (0,0) and (5,0), found by setting y=0:
x(5−x)=0
The y-intercept occurs when x=0, giving the point (0,0).
For Line L (y = rac{5}{2}x + 2):
The x-intercept occurs when y=0. Solving:
ightarrow x = -rac{4}{5}$$
The y-intercept occurs when x=0, giving the point (0,2).
When sketching:
Curve C is a downward-opening parabola with its vertex at (2.5,6.25) (calculated at x=2.5).
Line L has a positive slope and passes through (0,2) and approximately (1.6,6).
Make sure to label the x-intercepts and y-intercepts of both curves clearly.