SOLUTION: What is the inverse of Y=(X+3)² ?

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Question 1210394: What is the inverse of Y=(X+3)² ?
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
X=%28Y%2B3%29%5E2, but there are two of them. Try solve for Y and you'll see.

Answer by ikleyn(52775) About Me  (Show Source):
You can put this solution on YOUR website!
.
What is the inverse of Y=(X+3)² ?
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The direct function (which is the given function) does the following:

    - it adds the number 3 to the argument and then squares the value.


Therefore, the range of the given function is the set of all non-negative real numbers.



It means that the domain of the inverse function is the set of all non-negative real  numbers,
and at this set the inverse function makes the opposite operations in reverse order:

    - first, it takes square root from the value, and after that subtract 3 from the square root.


So, we can write an expression for the inverse function

    g(x) = sqrt%28x%29 - 3.



But square root from a real number can be positive or negative.
Therefore, there are TWO possible expressions for "the" inverse function.


First  expression is  p(x) = sqrt%28x%29 - 3,   using positive value of sqrt%28x%29.


Second expression is  q(x) = -sqrt%28x%29 - 3,  using negative value of sqrt%28x%29. 


These two possible expressions define two possible inverse functions.


Both inverse functions are defined over the set of non-negative real numbers.


First inverse function has the range [-3,infinity).

Second inverse function has the range (-infinity,-3].

At this point,  the problem is solved completely,  with detailed explanations,  so everybody can understand.


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It is important to note that the question in the problem is not precisely correct/accurate.

Indeed,  it asks   " what is the inverse function of  Y = %28X%2B3%29%5E2  ?"

To be correct,  in this situaion,   the question should ask   " what are possible inverse functions of  Y = %28X%2B3%29%5E2  ?"


        Now,  after reading my post,  you are armed to the teeth:
        you know the right question and also know the right answer.


Come again to this forum soon to learn something new from the best source.