∫(上π,下π/2)xf(sinx)dx=(令t=x-π/2)
=∫(上π/2,下0)(t+π/2)f(sint)dt
=∫(上π/2,下0)tf(sint)dt+π/2∫(上π/2,下0)f(sint)dt
π/2∫(上π,下π/2)f(sinx)dx=(令t=x-π/2)
=π/2∫(上π/2,下0)f(sint)dt
看清楚了,后面的同理也可以证到
∫(上π,下π/2)xf(sinx)dx=(令t=x-π/2)
=∫(上π/2,下0)(t+π/2)f(sint)dt
=∫(上π/2,下0)tf(sint)dt+π/2∫(上π/2,下0)f(sint)dt
π/2∫(上π,下π/2)f(sinx)dx=(令t=x-π/2)
=π/2∫(上π/2,下0)f(sint)dt
看清楚了,后面的同理也可以证到