SOLUTION: find the domain and range of f(x) = (x)/(sqrt(1 - ((sqrt(- x)))^2))

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Question 1210376: find the domain and range of f(x) = (x)/(sqrt(1 - ((sqrt(- x)))^2))
Found 2 solutions by mccravyedwin, Edwin McCravy:
Answer by mccravyedwin(406) About Me  (Show Source):
You can put this solution on YOUR website!
   

find the domain and range of f%28x%29%22%22=%22%22%28x%5E%22%22%5E%22%22%29%2F%28sqrt%281+-+%28sqrt%28-x%29%29%5E2%29%29



x cannot be positive but can be 0. The denominator is always positive.
So the value of f is never positive but can be 0 when x=0.

What is under the radical in the denominator must be positive, not negative or
0.  Remember that -x can never be negative.

1-%28sqrt%28-x%29%29%5E2%22%22%3E%22%220
-%28sqrt%28-x%29%29%5E2%22%22%3E%22%22-1
%28sqrt%28-x%29%29%5E2%22%22%3C%22%221
-x%22%22%3C%22%22%7B%7B%7B%22%22%3C%22%221
x%22%22%3E%22%22-1

Remember again that -x is non-negative. 

-x%22%22=%22%221

x%22%22=%22%22-1 and since x is never positive but can be 0,

the domain is -1%3Cx%3C=0

We set the denominator = 0 to find the vertical asymptote:

sqrt%281+-+%28sqrt%28-x%29%29%5E2%29%22%22=%22%220

1+-+%28sqrt%28-x%29%29%5E2%22%22=%22%220

-%28sqrt%28-x%29%29%5E2%22%22=%22%22-1

%28sqrt%28-x%29%29%5E2%22%22=%22%221

Remember that -x is non-negative. 

-x%22%22=%22%221

x%22%22=%22%22-1

So the vertical asymptote is x%22%22=%22%22-1, indicated by the green line.

The domain is matrix%281%2C5%2C%22%28%22%2C-1%2C%22%2C%22%2C0%2C%22%5D%22%29

The range is matrix%281%2C5%2C%22%28%22%2C-infinity%2C%22%2C%22%2C0%2C%22%5D%22%29

Edwin

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
Notice that I have added something to the above answer.  This part:

What is under the radical in the denominator must be positive, not negative or
0.  Remember that -x can never be negative.

1-%28sqrt%28-x%29%29%5E2%22%22%3E%22%220
-%28sqrt%28-x%29%29%5E2%22%22%3E%22%22-1
%28sqrt%28-x%29%29%5E2%22%22%3C%22%221
-x%22%22%3C%22%22%7B%7B%7B%22%22%3C%22%221
x%22%22%3E%22%22-1

Remember again that -x is non-negative. 

-x%22%22=%22%221

x%22%22=%22%22-1 and since x is never positive but can be 0,

the domain is -1%3Cx%3C=0

Edwin