1 / | | 1 | 1*-------- dx | cos(4*x) | / 0
/ | | 1 | 1*1*-------- dx | cos(4*x) | /
1 1*-------- cos(4*x)
cos(4*x)
1 1*cos(4*x) 1*-------- = ---------- cos(4*x) 2 cos (4*x)
sin(a)^2 + cos(a)^2 = 1
2 2 cos (4*x) = 1 - sin (4*x)
1*cos(4*x) 1*cos(4*x) ---------- = ------------- 2 2 cos (4*x) 1 - sin (4*x)
u = sin(4*x)
/ | | 1*cos(4*x) | ------------- dx | 2 = | 1 - sin (4*x) | /
/ | | 1*cos(4*x) | ------------- dx | 2 = | 1 - sin (4*x) | /
/ | | 1 | ---------- du | / 2\ | 4*\1 - u / | /
1 1*1/4 / 1 1 \ ---------- = -----*|----- + -----| / 2\ 2 \1 - u 1 + u/ 4*\1 - u /
/ / | | | 1 | 1 | ----- du | ----- du / | 1 + u | 1 - u | | | | 1 / / = | ---------- du = ----------- + ----------- | / 2\ 8 8 | 4*\1 - u / | /
= -log(-1 + u)/8 + log(1 + u)/8
u = sin(4*x)
/ | | 1 log(-1 + sin(4*x)) log(1 + sin(4*x)) | 1*1*-------- dx = - ------------------ + ----------------- + C0 | cos(4*x) 8 8 | /
/ | | 1 log(-1 + sin(4*x)) log(1 + sin(4*x)) | 1*-------- dx = C - ------------------ + ----------------- | cos(4*x) 8 8 | /
nan
=
nan
Данные примеры также можно применять при вводе верхнего и нижнего предела интегрирования.