不等式问题1设实数x,y满足x^2+(y
设实数x,y满足x^2+(y-1)^2=1,当x+y+c≥0时，c的取值范围是多少？
设x=cosa ,y =1+sina x+y+c≥0 ==>c≥ -x-y =-cosa-1-sina =-√2[sin(a+π/4)-1 ==> -√2-1≤c≤√2 -1