f(x)=log(2)x+log(x)2x的值域 注:()中的数表示底数

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f(x)=log(2)x+log(x)2x的值域注:()中的数表示底数f(x)=log(2)x+log(x)2x的值域注:()中的数表示底数f(x)=log(2)x+log(x)2x的值域注:()中的

f(x)=log(2)x+log(x)2x的值域 注:()中的数表示底数
f(x)=log(2)x+log(x)2x的值域 注:()中的数表示底数

f(x)=log(2)x+log(x)2x的值域 注:()中的数表示底数
h(t)=t+1/t(t不等于0)的值域是(-无穷,-2]U[2,+无穷)
f(x)=log(2)x+log(x)2x=log(2)x+1/log(2)x+1
log(2)x+1/log(2)x的定义域是(0,1)U(1,+无穷),值域是(-无穷,-2]U[2,+无穷).
所以,f(x)=log(2)x+log(x)2x=log(2)x+1/log(2)x+1的值域是(-无穷,-1]U[3,+无穷)

f(x) = log(2)x + log(x)[2x]
零和负数无对数,x>0;底数>0并且≠1
定义域:x∈(0,1),(1,+∞)
f(x) = log(2)x + log(x)[2x]
= log(2)x + log(x)2 + log(x)x
= log(2)x + log(x)2 + 1
= lgx / lg2 + lg2/lgx + 1<...

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f(x) = log(2)x + log(x)[2x]
零和负数无对数,x>0;底数>0并且≠1
定义域:x∈(0,1),(1,+∞)
f(x) = log(2)x + log(x)[2x]
= log(2)x + log(x)2 + log(x)x
= log(2)x + log(x)2 + 1
= lgx / lg2 + lg2/lgx + 1
当x∈(0,1)时:
= -(-lgx / lg2 - lg2/lgx) + 1
= - [√(-lgx / lg2) - √(-lg2/lgx)]^2 - 2 + 1
= - [√(-lgx / lg2) - √(-lg2/lgx)]^2 - 1 ≤ -1
当x∈(1,+∞)时:
= [√(lgx / lg2) - √(lg2/lgx)]^2 + 2 + 1
= [√(lgx / lg2) - √(lg2/lgx)]^2 +3 ≥3
值域(-∞,-1),(3,+∞)

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