Better: (R_n = \frac2n \sum_i=1^n (4 + \frac6in) = \frac2n[4n + \frac6n\cdot \fracn(n+1)2] = \frac2n[4n + 3(n+1)] = 14 + \frac6n)
: (\int_0^2 x^2 dx = \fracx^33 \Big|_0^2 = \frac83 \approx 2.6667)
[ \int_a^b f(x) , dx = \lim_n \to \infty \sum_i=1^n f(x_i^*) \Delta x ] sumas de riemann ejercicios resueltos pdf
Exact: (\int_1^3 (3x+1)dx = \left[\frac3x^22 + x\right]_1^3 = \left(\frac272+3\right) - \left(\frac32+1\right) = (13.5+3)-(1.5+1)=16.5-2.5=14)
[ M_4 \approx \frac\pi2 \times 1.306563 \approx 1.896 ] Better: (R_n = \frac2n \sum_i=1^n (4 + \frac6in)
Note: (\sin(5\pi/8) = \sin(3\pi/8),\ \sin(7\pi/8) = \sin(\pi/8))
Numerically: (\sin(22.5^\circ) \approx 0.382683,\ \sin(67.5^\circ) \approx 0.923880), sum (\approx 1.306563) \ \sin(67.5^\circ) \approx 0.923880)
So: [ M_4 = \frac\pi4 \left[ 2\sin(\pi/8) + 2\sin(3\pi/8) \right] = \frac\pi2 [\sin(22.5^\circ) + \sin(67.5^\circ)] ]