1.

The range of the function `f(x)=(x)/(1+x^(2))` isA. `[0,1//2]`B. `[-1//2,1//2]`C. `[-1//2,0]`D. `[-1//2,0) cup (0,1//2]`

Answer» Correct Answer - B
Clearly, f(x) is defined for all ` x in R. `
So, domain (f)=R
In order to find the range of f(x) , let
y=f(x)
`implies y=(x)/(x+x^(2)`
`implies x^(2)y-x+y=0`
`implies x=(1 pm sqrt(1-4y^(2)))/(2y)`
For x to be real, we must have
`1-4y^(2) ge 0 and y ne 0 implies -(1)/(2) le y le (1)/(2) and y ne 0`
Also , y=-0 for x=0
Hence, range of f(x)=[-1/2,1/2]


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