1、y=4^x+2^(x+1)+1 =(2^x)^2+2*2^x+1=(2^x+1)^2
定義域?yàn)椋簒屬于實(shí)數(shù)集R,
2^x>0,+1>1,(2^x+1)^2>1,值域y>1
在實(shí)數(shù)范圍內(nèi),2^x是單調(diào)增加的,y也是單調(diào)增加的
2、y=(1/3)^(x^2-3x+2)=y=(1/3)^[(x-1)^2+1]
定義域?yàn)椋簒屬于實(shí)數(shù)集R
(x-1)^2+1>=1,0<=(1/3)^[(x-1)^2+1]<=(1/3)^1=1/3
值域?yàn)椋?,1/3]
當(dāng)x>1時(shí),(x-1)^2+1單調(diào)增,而(1/3)^[(x-1)^2+1]單調(diào)減,
當(dāng)x<1時(shí),(x-1)^2+1單調(diào)減,而(1/3)^[(x-1)^2+1]單調(diào)增
y=(1/3)^(x^2-3x+2)在1到正無窮大是單調(diào)減
在負(fù)無窮大到1是單調(diào)增