1设随机变量的密度函数为(m)=Jqr,当≤1 0.其它 (1)常数c的值 (i)-≤s≤0的概率 (i)的数学期望E和方差D 、计算题(2×10=20(分) (12)设f(u)在u∈R上有二阶连续导数,2(x,y)=f(1+ry) (i)求zx,zxy,z i)若f(0)=0.,且2(x,y)满足方程: y)+ zry=1+ 求f(u)(11)‘ÅCþξݼêf(x) =    c|x|, |x| ≤ 1; 0, Ù§ ¦µ (i)~êcŠ¶ (ii)− 4 3 ≤ ξ ≤ 0VǶ (iii)ξêÆÏ"EξڐDξ. n!OŽK(2 × 10 = 20(©)) (12)f(u)3u ∈ RþkëYê§z(x, y) = f(1 + xy). (i)¦zxx, zxy, zyy; (ii)ef(0) = 0, …z(x, y)÷v§µ 1 x 2 + y 2 (zxx + zyy) + zxy = 1 + xy ¦f(u). 5