NIntegrate(f(x), x, a, b)
Finds the definite integral of the given function by a numerical integration method. The limits of integration are a (lower limit) and b (upper) limit.

Examples
NIntegrate(sin(x), x, 0, #pi)
1.9999999999999993
NIntegrate(cos(x), x, -#pi/2, #pi/2)
1.9999999999999993

References

Related Functions
A
B
C
D
E
F
G
H
I
J
K
L
M
N
P
Q
R
S
T
V
W
Z