∫[0：π][f(x)+f''(x)]sinxdx
=∫[0：π]f(x)sinxdx+∫[0：π]sinxd[f'(x)]
=∫[0：π]f(x)sinxdx+sinxf'(x)|[0：π]-∫[0：π]f'(x)d(sinx)
=∫[0：π]f(x)sinxdx-∫[0：π]f'(x)cosxdx
=∫[0：π]f(x)sinxdx-∫[0：π]cosxd[f(x)]
=∫[0：π]f(x)sinxdx -f(x)cosx|[0：π]+∫[0：π]f(x)d(cosx)
=∫[0：π]f(x)sinxdx -[f(π)cosπ-f(0)cos0]-∫[0：π]f(x)sinxdx
=-[[b·(-1)-a·1]
=a+b
内容全部来源于网络收集，如有侵权，请联系网站删除!