(1)设随机变量的密度函数为f=cos,当叫≤立求 其它 i)常数c的值; 3丌 (i)-≤5≤0的概率 (i)1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,z(x,y)=f( e sin y) (i)求zx,zy i)若f(0)=0.,f(0)=1,且x(x,y)满足方程 求f(u)(11)‘ÅCþξݼêf(x) =    c cos x, |x| ≤ π 2 ; 0, Ù§ ¦µ (i)~êcŠ¶ (ii)− 3π 4 ≤ ξ ≤ 0VǶ (iii)ξêÆÏ"EξڐDξ. n!OŽK(2 × 10 = 20(©)) (12)f(u)3u ∈ RþkëYê§z(x, y) = f(e x sin y). (i)¦zxx, zyy; (ii)ef(0) = 0, f0 (0) = 1, …z(x, y)÷v§µ zxx + zyy = e 2x z ¦f(u). 5