代换t=x-π/2,代入得:∫(0,π)(e^cosx-e^(-cosx))dx =∫(-π/2,π/2)(e^cos(π/2+t)-e^(-cos(π/2+t))dt =∫(-π/2,π/2)(e^(-sint)-e^(sint))dt 由于被积函数是奇函数,区间对称,故积分为0