Integrate[
2/L*2/V*2/W*Sin[(t*\[Pi])/L*(x + L/2)]*Sin[(r*\[Pi])/V*(y + V/2)]*
Sin[(s*\[Pi])/W*(z + W/2)]*\[Alpha]/\[Sqrt](x^2 + y^2 + z^2)*
Sin[(t*\[Pi])/L*(x + L/2)]*Sin[(r*\[Pi])/V*(y + V/2)]*
Sin[(s*\[Pi])/W*(z + W/2)], {x, -L/2, L/2}, {y, -V/2, V/2}, {z, -W/
2, W/2},
Assumptions -> (Element[t, Integers] && Element[r, Integers] &&
Element[s, Integers])] \\ TraditionalForm

最后的反斜杠方向是不是反了//