Õuna ruumala määramine integraali abil

Joone \; y=f\left(   x\right) \; pööramisel \; ümber \; x
-telje \; rajadeks

x= \; a \; kuni \; x=b \; saame \; pöördkeha \; ruumala

A = (0, -3.14)
B = (7, -3.14)
C = (0.04, 2.16)
D = (0.36, 2.92)
E = (0.94, 3.74)
F = (2, 4)
G = (3.119040446062415, 4.582426006951354)
H = (4.4134736215929475, 4.15975394963526)
J = (5.655072789958969, 4.318255971128795)
K = (6.315497879515363, 3.0502397991805137)
N = (6.923088961907245, 1.7558066236499763)
O = (7.028756976236268, 0.7255434839419977)
I = (6.817420947578222, 2.6804017490289316)
f = Fit({C, D, E, F, G, H, J, K, N, O, I}, {1, x, x^(2), x^(3), x^(4), x^(5), x^(6), x^(7), x^(8)})
tekst1: "f\left(  x \right) = \; " + (LaTeX[f]) + ""
V: (π * Integral[(f(x))^(2), 0, 7])
V_{ligikaudne}: round(V)
tekst2: "V= π \int_{0}^{7}{f\left(  x \right) ^ 2 \; dx }= \; " + (LaTeX[V]) + "≈" + (LaTeX[V_{ligikaudne}]) + " \; cm^ 3"