例24.1设随机变量Xf(x)={v-x21k1求(1)A x≥1 (2)P{-1/2<X<12}; 解1)由性质2得∫。()k=∫ v-ra=1(3)P3X<2 即 Arcsin x=Am=1,所以A=1/r 2P12×12Jm2f(x)kmn dxe-arcsin x 1/ =1(/6+m/6)=1/3 (3)P(-3-X=2)=-/(x)ox=D 1 d 思考P1n2X=2例2.4.1 设随机变量X~        = − 0 | | 1 | | 1 ( ) 1 2 x x x A f x 求(1)A; (2)P{-1/2<X<1/2}; (3)P{-3<X<2} 解:(1)由性质2得:   +  − − = − = 1 1 2 1 1 ( ) dx x A f x dx 即 = −1 1 Aarcsin x Aπ=1, 所以 A=1/π (2)P{-1/2<X<1/2}= − = 1/ 2 1/ 2 f (x)dx − − 1/ 2 1/ 2 2 1 1 dx  x 1/ 2 1/ 2 arcsin 1 − = x  =1/π(π/6+π/6)=1/3 (3)P{-3<X<2}= − 2 3 f (x)dx − − = 1 1 2 1 1 dx  x =1 思考: P{-1/2<X<2}= ?