Figure 1 shows part of the curve with equation $y = e^{0.5x}$ - Edexcel - A-Level Maths Pure - Question 4 - 2008 - Paper 7
Question 4
Figure 1 shows part of the curve with equation $y = e^{0.5x}$. The finite region $R$, shown shaded in Figure 1, is bounded by the curve, the x-axis, the y-axis and t... show full transcript
Worked Solution & Example Answer:Figure 1 shows part of the curve with equation $y = e^{0.5x}$ - Edexcel - A-Level Maths Pure - Question 4 - 2008 - Paper 7
Step 1
Complete the table with the values of $y$ corresponding to $x = 0.8$ and $x = 1.6$
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Answer
To find the values for y when x=0.8 and x=1.6, we can use the equation y=e0.5x:
For x=0.8:
y=e0.5imes0.8=e0.4≈1.49182 (rounded to 5 significant figures)
For x=1.6:
y=e0.5imes1.6=e0.8≈2.22554 (rounded to 5 significant figures)
Thus, the completed table with approximate values is:
x
0
0.4
0.8
1.2
1.6
2
y
1.0
1.49182
1.64872
2.22554
3.68078
7.38906
Step 2
Use the trapezium rule with all the values in the table to find an approximate value for the area of $R$
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Answer
To apply the trapezium rule, we need to calculate the area using the formula:
A = rac{1}{2}ht(a+b) + h \\sum_{i=1}^{n-1}y_i
where A is the area, h is the width of the trapezium, a and b are the heights of the first and last sections respectively, and yi are the intermediate heights.
Width of each sub-interval (h):
The interval is [0,2], thus h=0.4.
The values of y from the table are approximately: 1.0,1.49182,1.64872,2.22554,3.68078,7.38906