f(x)= ∫ (下限x上限x+π\2) |sint| dt ,证明f(x)是以π为周期的周期函数

ƒ(x) = ∫(x→x + π/2) |sint| dtƒ(x + π) = ∫(x + π→x + 3π/2) |sint| dt令t = y + π,dy = dxƒ(x + π) = ∫(x→x + π/2) |sin(y + π)| dy= ∫(x→x + π/2) |siny| dy= ∫(x→x + π/2) |...