Mathematics
22 Online
OpenStudy (imterribleatmath):
will give medal for anwser.
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (eliesaab):
What is f(g(x))?
OpenStudy (eliesaab):
\[
f(g(x)) =\sqrt{8(x-3)}
\]
OpenStudy (eliesaab):
When is the square root defined? Can you take \(\sqrt {-5}\) as a real number?
OpenStudy (eliesaab):
Are you with me?
OpenStudy (imterribleatmath):
i just do not understand
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (eliesaab):
To be able to take the square root of a number, this number must be positive or zero. Do you know that?
OpenStudy (imterribleatmath):
i did not.
OpenStudy (eliesaab):
Do now
OpenStudy (eliesaab):
For example
\[
\sqrt{25}=5
\]
but \[
\sqrt{-25}
\]
is not a real number and is therefore not defined as such
OpenStudy (imterribleatmath):
ok got it
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (eliesaab):
What is under the square root in your composed function
\[
f(g(x))=\sqrt{ 8(x-3)}
\]
?
OpenStudy (eliesaab):
What is under the square root is
\[
8(x-3)
\]
this quantity must be \( \ge 0\)
OpenStudy (eliesaab):
What values of x will do that?
OpenStudy (imterribleatmath):
do i solve for x?
OpenStudy (eliesaab):
\[
(x-3)\ge 0\\
x\ge 3
\]
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (eliesaab):
So the domain is
\[
[3, \infty[
\]
OpenStudy (eliesaab):
What is the smallest number in this interval?
OpenStudy (imterribleatmath):
wouldnt it be 3?
OpenStudy (eliesaab):
Yes
OpenStudy (eliesaab):
So what is the answer?
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (imterribleatmath):
is it 3? how would i find out the smallest number
OpenStudy (eliesaab):
Yes it is 3.
If the numbers you are dealing with are 3 and all the numbers bigger than 3.
What would be the smaller one?
OpenStudy (imterribleatmath):
the 3
OpenStudy (imterribleatmath):
so the smallest number in the domain is 3 ?
OpenStudy (imterribleatmath):
was correct thanks
Join the QuestionCove community and study together with friends!
Sign Up
OpenStudy (eliesaab):
yes