x^2-5a-3>=根号(x^2-8) x^4+(5a+3)^2-(5a+3)x^2>=x^2-8 x^4+(5a+3)^2+8-(5a+2)x^2>=0 (x^2-5a-3)(x^2+1)>=0 因为x^2+1>0,所以x^2-5a-3>=0 p为真,所以-5a-3>=0 a<=-3/5
(x^2-4)x^2+(a+2)x-1>=0 q为假,则有解.
x^4-4x^2+ax+2x-1>=0
德尔塔>=0,16-4(ax+2x-1)>=0
5-ax-2x>=0,a<=5-2x/x=(5/x)-2 x