(1)y=ln(x+1)对数函数中真数要大于0∴x+1>0→x>-1定义域(-1,+∞)(2)y=arcsin(x-3)∵y=arcsinx的定义域为[-1,1]∴-1≤x-3≤1→2≤x≤4定义域[2,4](3)y=2x/(x-3x+2)分母不为0即x-3x+2≠0(x-2)(x-1)≠0→x≠2或x≠1定义域{x|x∈R且x≠1,x≠2}