令f(x)=x-sinx;其导数f'(x)=1-cosx≥0,可知f(x)在定义域R上是增函数.而f(x)的极限lim(x→-∞)f(x)=lim(x→-∞)x-lim(x→-∞)sinx =-∞lim(x→+∞)f(x)=lim(x→+∞)x-lim(x→+∞)sinx =+∞那么根据零值定理,在区间(-...