y=4^0.5*4^x-3*2^x+5=2*(2^x)^2-3*2^x+5令t=2^x,0<=x<=2,1<=t<=4y=2t^2-3t+5=2(t-3/4)^2+31/8在1<=t<=4时,函数单调递增,所以最大值为25(t=4时),最小值为4(t=1时)
令t=2^x,0<=x<=2,1<=t<=4y=2t^2-3t+5=2(t-3/4)^2+31/8在1<=t<=4时,函数单调递增,所以最大值为25(t=4时),最小值为4(t=1时