pi / | | x*sin(x)*cos(n*x) dx | / -pi
Integral((x*sin(x))*cos(n*x), (x, -pi, pi))
// 2 2 \
|| x*cos (x) x*sin (x) cos(x)*sin(x) |
|| - --------- + --------- + ------------- for Or(n = -1, n = 1)|
/ || 4 4 4 |
| || |
| x*sin(x)*cos(n*x) dx = C + |< 2 2 3 |
| ||cos(n*x)*sin(x) n *cos(n*x)*sin(x) x*cos(x)*cos(n*x) 2*n*cos(x)*sin(n*x) x*n *cos(x)*cos(n*x) x*n *sin(x)*sin(n*x) n*x*sin(x)*sin(n*x) |
/ ||--------------- + ------------------ - ----------------- - ------------------- + -------------------- + -------------------- - ------------------- otherwise |
|| 4 2 4 2 4 2 4 2 4 2 4 2 4 2 |
|| 1 + n - 2*n 1 + n - 2*n 1 + n - 2*n 1 + n - 2*n 1 + n - 2*n 1 + n - 2*n 1 + n - 2*n |
\\ /
/ -pi | ---- for Or(n = -1, n = 1) | 2 | < 2 |2*pi*cos(pi*n) 4*n*sin(pi*n) 2*pi*n *cos(pi*n) |-------------- + ------------- - ----------------- otherwise | 4 2 4 2 4 2 \1 + n - 2*n 1 + n - 2*n 1 + n - 2*n
=
/ -pi | ---- for Or(n = -1, n = 1) | 2 | < 2 |2*pi*cos(pi*n) 4*n*sin(pi*n) 2*pi*n *cos(pi*n) |-------------- + ------------- - ----------------- otherwise | 4 2 4 2 4 2 \1 + n - 2*n 1 + n - 2*n 1 + n - 2*n
Piecewise((-pi/2, (n = -1)∨(n = 1)), (2*pi*cos(pi*n)/(1 + n^4 - 2*n^2) + 4*n*sin(pi*n)/(1 + n^4 - 2*n^2) - 2*pi*n^2*cos(pi*n)/(1 + n^4 - 2*n^2), True))
Use the examples entering the upper and lower limits of integration.