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Mathematics 16 Online
OpenStudy (anonymous):

please help step by step :) f(x)={x+2 , if x<0 {1-x , if x>=0

OpenStudy (anonymous):

What's the question?

OpenStudy (anonymous):

I need to find the domain and sketch the graph of the function.

OpenStudy (anonymous):

OK, so the domain is every value of x that we can put into the function. Since f(x) is defined for both x<0 and x>=0, we can see that we can put in any value of x that we want, so the domain will be the real numbers. Do you understand this bit?

OpenStudy (anonymous):

so basically the domain will be any real numbers that are <0 or >=0 ?

hartnn (hartnn):

but its good to write that x belongs to real number

OpenStudy (anonymous):

so is it x+2>0 and 1-x>=0 x>-2 and x>=1 ?

hartnn (hartnn):

no,for domain u see for what values of x, f(x) is defined. here it is defined for all real values of x. anything else is not required/correct.

OpenStudy (anonymous):

.... I'm confused?

hartnn (hartnn):

domain is (-infinity,infinity)

OpenStudy (anonymous):

how is it though?

hartnn (hartnn):

because the function is defined for every value of x from -infinity to infinity as explained already.

hartnn (hartnn):

with no restrictions on x

OpenStudy (anonymous):

oh okay sorry. I had to re-read it all to understand it. and to graph it I just input x+2 and 1-x and press graph on my calculator which creates |dw:1346193941346:dw| which is why the domain is (-inf,inf)?

OpenStudy (anonymous):

because the lines go on.

hartnn (hartnn):

yes,if there's a break or discontinuity,then at that value,f(x) will not be defined,and that point will be removed from the domain.

OpenStudy (anonymous):

okay thank you!

hartnn (hartnn):

welcome :)

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