Domain of Rational Square Root Function

Find the Domain of the Function

Question:

The domain of definition of

\[ f(x)=\sqrt{\frac{x+3}{(2-x)(x-5)}} \]

is

(a) \((-\infty,-3]\cup(2,5)\)
(b) \((-\infty,-3)\cup(2,5)\)
(c) \((-\infty,-3]\cup[2,5]\)
(d) none of these

Solution:

For square root function,

\[ \frac{x+3}{(2-x)(x-5)}\ge0 \]

Critical points are

\[ x=-3,\;2,\;5 \]

Using sign analysis,

\[ \frac{x+3}{(2-x)(x-5)}\ge0 \]

for

\[ (-\infty,-3]\cup(2,5) \]

Note that \(x=2\) and \(x=5\) are excluded because denominator becomes zero.

Therefore,

\[ \boxed{(-\infty,-3]\cup(2,5)} \]

\[ \boxed{\text{Correct Answer: (a)}} \]

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