1
f(x) = 1.31 + 1.45 x

2
f1(x) = -0.40 + 2.42 x
f2(x) =  1.22 + 1.57 x + 0.083 x^2

3
0.40

4
 1.233700558
 4.93769410
11.14670296
25.06230590
43.86959649

5
N         Euler           mid-rect        trap
 100      13769.61235     21599.25828     21677.41442
1000      20948.15569     22011.24467     22011.82242