Figure 2 shows part of the curve with equation $y = f(x)$ - Edexcel - A-Level Maths Pure - Question 6 - 2012 - Paper 5
Question 6
Figure 2 shows part of the curve with equation $y = f(x)$.
The curve passes through the points $P(-1.5, 0)$ and $Q(0, 5)$ as shown.
On separate diagrams, sketch the... show full transcript
Worked Solution & Example Answer:Figure 2 shows part of the curve with equation $y = f(x)$ - Edexcel - A-Level Maths Pure - Question 6 - 2012 - Paper 5
Step 1
Sketch the curve with equation $y = f(-x)$
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Answer
To reflect the curve across the y-axis, take each point on the original curve and change the sign of the x-coordinate. The key points to plot are:
Original point P(−1.5,0) becomes P′=(1.5,0)
Original point Q(0,5) remains Q=(0,5)
After sketching, the curve should touch the x-axis at (1.5,0) and rise to (0,5).
Step 2
Sketch the curve with equation $y = |f(x)|$
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Answer
This transformation reflects any portion of the curve that lies below the x-axis to above it, keeping the parts above the x-axis unchanged. The coordinates to indicate are:
(0,5) stays as (0,5).
The point where the curve intersects the x-axis at P(−1.5,0) remains the same but any points from the original curve below the x-axis will now be reflected.
Visualize the transformation and draw the new curve, ensuring to display the key points accurately.
Step 3
Sketch the curve with equation $y = 2f(3x)$
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Answer
This equation scales the curve vertically by a factor of 2 and compresses it horizontally by a factor of 1/3. For the key coordinates:
At the original point P(−1.5,0), the new point will remain at (0,0) after transformation since f(−1.5) is 0.
For point Q(0,5), the new point will transform to (0,10) (as 5 multiplies by 2).
Calculate additional x-intercepts by setting y=0 to find further intercepts.
Ensure the sketch reflects these transformations accurately.