1 / | | 1 | 1*-------- dx | cos(2*x) | / 0
/ | | 1 | 1*1*-------- dx | cos(2*x) | /
1 1*-------- cos(2*x)
cos(2*x)
1 1*cos(2*x)
1*-------- = ----------
cos(2*x) 2
cos (2*x) sin(a)^2 + cos(a)^2 = 1
2 2 cos (2*x) = 1 - sin (2*x)
1*cos(2*x) 1*cos(2*x) ---------- = ------------- 2 2 cos (2*x) 1 - sin (2*x)
u = sin(2*x)
/ | | 1*cos(2*x) | ------------- dx | 2 = | 1 - sin (2*x) | /
/ | | 1*cos(2*x) | ------------- dx | 2 = | 1 - sin (2*x) | /
/ | | 1 | ---------- du | / 2\ | 2*\1 - u / | /
1 1*1/2 / 1 1 \ ---------- = -----*|----- + -----| / 2\ 2 \1 - u 1 + u/ 2*\1 - u /
/ /
| |
| 1 | 1
| ----- du | ----- du
/ | 1 + u | 1 - u
| | |
| 1 / / =
| ---------- du = ----------- + -----------
| / 2\ 4 4
| 2*\1 - u /
|
/
= -log(-1 + u)/4 + log(1 + u)/4
u = sin(2*x)
/ | | 1 log(-1 + sin(2*x)) log(1 + sin(2*x)) | 1*1*-------- dx = - ------------------ + ----------------- + C0 | cos(2*x) 4 4 | /
/ | | 1 log(-1 + sin(2*x)) log(1 + sin(2*x)) | 1*-------- dx = C - ------------------ + ----------------- | cos(2*x) 4 4 | /
nan
=
nan
Данные примеры также можно применять при вводе верхнего и нижнего предела интегрирования.