Question

How do you find the domain of `f(x)=sqrt(4-x^2)`?

Answer 1

Assuming we are restricted to Real values,
Domain of `f(x)` is `x in [-2,+2]`

Explanation:

For `sqrt(4-x^2)` to be a valid Real number

`4-x^2 >= 0` (the square root is not defined in Real numbers for negative arguments)

`rarr 4 >= x^2`

`rarr -2 <=x <= +2`