1.

Find the domain and the range of the real function, `f(x)=(1)/(sqrt(x+|x|))`.

Answer» We have, `f(x)=(1)/(sqrt(x+|x|))`
Now, `|x|={{:(x",when "xge0),(-x",when "xlt0):}`
`impliesx+|x|={{:(x+x",when "xge0),(x-x",when "xlt0):}`
`impliesx+|x|={{:(2x",when "xge0),(0",when "xlt0):}`
`impliesx+|x|gt0,"when "xgt0`
`impliesf(x)=(1)/(sqrt(x+|x|))` assumes real values only when `x+|x|gt0` and this happens only when `xgt0`.
`:."dom "(f)=(0,oo)`.


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