a / | | /3*pi*x\ /2*pi*x\ /3*pi*x\ /2*pi*x\ | sin|------|*cos|------|*cos|------|*cos|------| dx | \ a / \ a / \ a / \ a / | / 0
Integral(sin(3*pi*x/a)*cos(2*pi*x/a)*cos(3*pi*x/a)*cos(2*pi*x/a), (x, 0, a))
Use the examples entering the upper and lower limits of integration.