解:(1)当X∈(0,π/4)时,sinx∈(0,√2/2),cosx∈(√2/2,1),从而sin(sinx) ∈(0,sin(√2/2)),cos(sinx) ∈(cos(√2/2),1),sin(cosx) ∈(sin(√2/2),sin(1)),cos(cosx) ∈(cos(1),cos(√2/2))。因为,√2/2<π/4,sin1<1所以,sin(√2/2)<1<cos(√2/2)因此cos(sinx)最大。(2)设点的坐标分别是O(0,0),A(x1,0),B(x2,y2),C(x3,y3),由条件向量OA+2向量OB+3向量OC=0向量,知2y2+3y3=0即y2/y3=-3/2。因为,三角形AOC... |