1.x(x-3)(x+1)(x-2)<0 2.(30+7x-2x²)(x²+1)≤0
问题描述:
1.x(x-3)(x+1)(x-2)<0 2.(30+7x-2x²)(x²+1)≤0
答
1.x(x-3)(x+1)(x-2)<0 穿线法:──╮ ╭────╮ ╭─────------o-----o----------o-----o------------->-1╰─╯0 2╰─╯3 x解集为 (-1,0)U(2,3)2.(30+7x-2x²)(x²+1)≤0x²+1>0恒成立原...