pi -- 2 / | | 1 | ------ dx | sin(x) | / 0
Integral(1/sin(x), (x, 0, pi/2))
/ | | 1 | ------ dx | sin(x) | /
1 ------ sin(x)
sin(x)
1 sin(x) ------ = ------- sin(x) 2 sin (x)
sin(a)^2 + cos(a)^2 = 1
2 2 sin (x) = 1 - cos (x)
sin(x) sin(x) ------- = ----------- 2 2 sin (x) 1 - cos (x)
u = cos(x)
/ | | sin(x) | ----------- dx | 2 = | 1 - cos (x) | /
/ | | sin(x) | ----------- dx | 2 = | 1 - cos (x) | /
/ | | -1 | ------ du | 2 | 1 - u | /
-1 -1 / 1 1 \ ------ = ---*|----- + -----| 2 2 \1 - u 1 + u/ 1 - u
/ / | | | 1 | 1 | ----- du | ----- du / | 1 + u | 1 - u | | | | -1 / / = | ------ du = - ----------- - ----------- | 2 2 2 | 1 - u | /
= log(-1 + u)/2 - log(1 + u)/2
u = cos(x)
/ | | 1 log(-1 + cos(x)) log(1 + cos(x)) | ------ dx = ---------------- - --------------- + C0 | sin(x) 2 2 | /
/ | | 1 log(-1 + cos(x)) log(1 + cos(x)) | ------ dx = C + ---------------- - --------------- | sin(x) 2 2 | /
pi*I oo + ---- 2
=
pi*I oo + ---- 2
oo + pi*i/2
Estos ejemplos se pueden aplicar para introducción de los límites de integración inferior y superior.