Fig. 11 shows the cross-section of a school hall, with measurements of the height in metres taken at 1.5 m intervals from O.
\includegraphics{figure_11}
- Use the trapezium rule with 8 strips to calculate an estimate of the area of the cross-section. [4]
- Use 8 rectangles to calculate a lower bound for the area of the cross-section. [2]
The curve of the roof may be modelled by \(y = -0.013x^3 + 0.16x^2 - 0.082x + 2.4\), where \(x\) metres is the horizontal distance from O across the hall, and \(y\) metres is the height.
- Use integration to find the area of the cross-section according to this model. [4]
- Comment on the accuracy of this model for the height of the hall when \(x = 7.5\). [2]