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Express f(x) = |x-2| +|x+2| in the non-modulus form. Hence, sketch the graph of f.

User Workhorse
by
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1 Answer

1 vote
Recall that


|x|=\begin{cases}x&amp;\text{if }x\ge0\\-x&amp;\text{if }x<0\end{cases}

There are three cases to consider:

(1) When
x+2<0, we have
|x+2|=-(x+2) and
|x-2|=-(x-2), so


|x-2|+|x+2|=-(x-2)-(x+2)=-2x-4

(2) When
x+2\ge0 and
x-2<0, we get
|x+2|=x+2 and
|x-2|=-(x-2), so


|x-2|+|x+2|=-(x-2)+(x+2)=4

(3) When
x-2\ge0, we have
|x+2|=x+2 and
|x-2|=x-2, so


|x-2|+|x+2|=(x-2)+(x+2)=2x

So


|x-2|+|x+2|=\begin{cases}-2x-4&amp;\text{if }x<-2\\4&amp;\text{if }-2\le x<2\\2x&amp;\text{if }x\ge2\end{cases}
User Reegan Miranda
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6.7k points
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