Question

Find the domain of the piecewise function and evaluate it for the given values. Then use the drop down menu to select the correct symbols to indicate your answer in interval notation. If a number is not an integer then round it to the nearest hundredth. To indicate positive infinifty ( \infty ) type the three letters "inf". To indicate negative infinity(-\infty ) type "-inf" with no spaces between characters. f(x) = \left\lbrace \begin{array}{cc} x+1 & x<-2 \\ -2x-3 & x\ge -2 \end{array}\right. The domain is:AnswerAnswer,AnswerAnswerf(-3)=Answerf(-2)=Answerf(-1)=Answerf(0)=Answer

Answer 1

SOLUTION

Let us make a graph of the function

$\begin{gathered} f(x)=x+1\mleft\{x<-2\mright\} \\ f(x)=-2x-3\mleft\{x\ge-2\mright\} \end{gathered}$

This is shown below

(a) The domain is usually determined from the x-axis. From the graph, the domain is all real numbers, that is, it is infinite for both positive and negative values for x, as you can see that if the graph is extended, there is no limit for x-values that it can contain. So the domain is (-infinity, infinity)

Hence the answer, Domain is

(-inf, inf)

(b)

$f(-3)$

In

$\begin{gathered} f(x)=x+1\{x<-2\} \\ -3\text{ is less than -2, so -3 is valid here, so } \\ f(-3)=-3+1 \\ f(-3)=-2 \end{gathered}$

Hence, the answer is -2

(c)

$f(-2)$

In

$\begin{gathered} f(x)=-2x-3\{x\ge-2\} \\ -2\text{ is equal to -2, so we will put -2 for x here, so } \\ f(-2)=-2(-2)-3 \\ f(-2)=4-3 \\ f(-2)=1 \end{gathered}$

Hence, the answer is 1

(d)

$f(-1)$

In

$\begin{gathered} f(x)=-2x-3\{x\ge-2\} \\ -1\text{ is greater than -2, hence, it is valid, so we will put -1 for x here, so } \\ f(-1)=-2(-1)-3 \\ f(-1)=2-3 \\ f(-1)=-1 \end{gathered}$

Hence, the answer is -1

(e)

$f(0)$

In

$\begin{gathered} f(x)=-2x-3\{x\ge-2\} \\ 0\text{ is greater than -2, so we will put 0 for x here, so } \\ f(0)=-2(0)-3 \\ f(0)=0-3 \\ f(0)=-3 \end{gathered}$

Hence, the answer is -3