概车纶与款理统外 同时得以下计算公式 P{X≤ay=Fa=“fx)dx, P{X>a}=1-P{X≤}=1-F(a) =Jfx)dx-∫fx)dx -f(x)dx+f(x)dx-f(x)dx. (4)若f(x)在点x处连续，则有F'(x)=f(x)(4) 若 f (x) 在 点 x 处连续,则 有F(x) = f (x). P{X  a} = F(a) f (x)d x, a − = P{X  a} = 1 − P{X  a} f x x f x x a ( ) d ( ) d  −  − = − = 1− F(a) f x x f x x a ( )d ( )d    − − = + f (x)d x. a  = 同时得以下计算公式