2^(x^2+x)<=1/4 ^(x-2)
2^(x^2+x)<=2^2(2-x)
x^2+x<=4-2x
x^2+3x-4<=0
-4<=x<=1
1/16<=2^x<=2
y=4^(x+1/2) -2^x +5
=2*2^2x-2^x+5
=2(2^x-1/4)^2+5-1/8
当2^x=1/4
最小值=39/8
当2^x=2
最大值=11