Question

What is the domain of the function f(x) - 50 ? 5 + 720-2 {x: 0 < 20) {0, 1, 2, 3,.20} {a: 2 < 20} {0, 1, 2, 3,....19

Answer 1

The domain of a function f(x) is the set of values of the variable x for which the function is defined (has a defined finite value).

In the case of rational functions like this one, the function becomes undefined when the denominator is 0, so we can write:

`\begin{gathered} 5+\sqrt[]{20-x}=0 \\ \sqrt[]{20-x}=-5\longrightarrow\text{ there is no real value for x that will satisfy this condition} \end{gathered}`

As the square root will only give positive values or zero, there is no value of x that will make the square root be equal to -5. Then, this condition does not give us any discontinuity for f(x).

We have now to consider that the square root of (20-x) will not accept negative arguments in order to be in the realm of real numbers. So then, we have the condition:

`\begin{gathered} 20-x\ge0 \\ 20\ge x \\ x\le20 \end{gathered}`

Then, f(x) will not be defined for x that do not satisfy this condition.

We can conclude that f(x) is defined for all values of x that are equal or less than 20.

Answer: The domain is {x: x<=20}

Then