分离常数法求值域的问题
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分离常数法求值域的问题
1.f(x)=-2x+3/(x+1)
2.f(x)=4x+2/(3x+1) x∈[-2,-1/3)∪(-1/3,3)
1.f(x)=-2x+3/(x+1)
2.f(x)=4x+2/(3x+1) x∈[-2,-1/3)∪(-1/3,3)
![分离常数法求值域的问题](/uploads/image/z/2230368-24-8.jpg?t=%E5%88%86%E7%A6%BB%E5%B8%B8%E6%95%B0%E6%B3%95%E6%B1%82%E5%80%BC%E5%9F%9F%E7%9A%84%E9%97%AE%E9%A2%98)
1.f(x)=-2x+3/(x+1)=[-2(x+1)+5]/(x+1)=-2+5/(x+1)
f(x)≠-2
2.f(x)=4x+2/(3x+1) =[4/3(3x+1)+2/3]/(3x+1) =4/3+2/3/(3x+1)
f(x)≠4/3 x∈[-2,-1/3)∪(-1/3,3)
f(x)∈[ 4/3+2/3/(3(-2)+1) ,4/3)∪( 4/3,4/3+2/3/(3(3)+1) )
f(x)≠-2
2.f(x)=4x+2/(3x+1) =[4/3(3x+1)+2/3]/(3x+1) =4/3+2/3/(3x+1)
f(x)≠4/3 x∈[-2,-1/3)∪(-1/3,3)
f(x)∈[ 4/3+2/3/(3(-2)+1) ,4/3)∪( 4/3,4/3+2/3/(3(3)+1) )