[填空题]
The following diagram shows a section of a curvasg*nyuxg* +y/lc p ,3e y=f(x) and the co a0wo8 2:bm +-mjtzq e,iu;rofordinates of six points that lie on the cue,bu-o:f 0 zommr28w+qaj t;irve.
1. Estimate the area of the shaded region, giving your answer to two decimal places.
$\int_{1}^{5} y \mathrm{~d} x$ $\approx$ units^2
The equation of the curve was found to be y=2 $x^{2}-4 x+20$ .
2. Write an integral that represents the area of the shaded region.
A= $\int_{1}^{5}\left(a x^{2}-b x+c\right) \mathrm{d} x$; a= ,b= ,c= .
3 . Find the area of the shaded region, giving your answer in exact values.
A=$\frac{a}{b}$ $units^2$ ; a= ,b= .
4. Find the percentage error between the estimation in part (a) and the exact value found in part (c).
