How do you graph #y=sqrtx+4#, compare it to the parent graph and what is the domain and range?

1 Answer
Jan 26, 2018

domain is #{x: x>=0 and x in RR}#
range is #color(white)("d."){y: y>=4 and y in RR}#
The transformation is #y=sqrt(x)# raised vertically by 4

Explanation:

You have a problem with this.

Apparently if you write #sqrt("something")# it is considered as representing the principle root. That is; the answer excludes the negative side of the squared values that will give #"something"# when squared.

So you have the general shape of #sub# but only the top half of it.

Adding 4 raises that plot up the #y# axis by 4

To avoid going into complex numbers the value being square rooted must be 0 or greater.

So we have the condition #x>=0#

Thus the domain is #{x: x>=0 and x in RR}#

When #x=0# we have #y=sqrt0+4=4#

So the range is #{y: y>=4 and y in RR}#

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Did you know that this is the same graph as:

#x=(y-4)^2 = y^2-8y+16#

That is: a quadratic in #y#