How do you find the domain of #f(x)=x^3-8x+4#?

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Answer 1 · 2018-06-14T19:14:27

#x inRR#

We're dealing with a polynomial here, which is defined for all real numbers. Let's think for a moment:

Are there any values of #x# that will make my function undefined?

Let's plug in some values for #x#:

#f(3)=(3)^3-8(3)+4=color(blue)(7)#

#f(11)=(11)^3-8(11)+4=color(blue)(1247)#

#f(41)=(41)^3-8(41)+4=color(blue)(68597)#

Notice, I could have picked much more ridiculous values for #x#, but we see that it is defined for all real numbers. We can say

#x inRR#

Hope this helps!