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# C3 inverse functions!?

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1. just wanted to check my answer to a question-
if g(x)=(x+1)^2 +2 for x>0 is my original function, would the inverse be =
+/- √x-2 -1?
then i thought can't be a function as it is not a one-one function, so as the domain was x>0 i thought it would be a positive square root..but then when i sketch it, that won't be a reflection in the y=x axis as it should be.
and i'm also getting myself muddled with the domains and ranges of each. would the domain for original/range for inverse be x>0 and the range of original/domain of inverse be x>-2?
the more i look at it the more i'm confusing myself
thankyou!
2. (Original post by georgiaaaxo)
just wanted to check my answer to a question-
if g(x)=(x+1)^2 +2 for x>0 is my original function, would the inverse be =
+/- √x-2 -1?
then i thought can't be a function as it is not a one-one function, so as the domain was x>0 i thought it would be a positive square root..but then when i sketch it, that won't be a reflection in the y=x axis as it should be.
and i'm also getting myself muddled with the domains and ranges of each. would the domain for original/range for inverse be x>0 and the range of original/domain of inverse be x>-2?
the more i look at it the more i'm confusing myself
thankyou!
The positive square root is correct. However the domain for your inverse should be x>3. You will then see the reflection in the line y=x.
3. for the question as stated x>0 is the domain
so if x>0 what is (x+1)2 +2 greater than?
4. (Original post by Lord of the Flies)
The positive square root is correct. However the domain for your inverse should be x>3. You will then see the reflection in the line y=x.
ohhh! of course. not sure where i got -2 from. thankyou!
5. (Original post by sputum)
for the question as stated x>0 is the domain
so if x>0 what is (x+1)2 +2 greater than?
x is greater than 3! thankyou

when i draw the graph, do i only draw the one positive line? i'm still a little confused as to how it is a reflection. the first one is a 'smiley face' quadratic right?
so how can the inverse be a reflection if you're only sketching the positives?
sorry for the questions, i missed the lesson on this topic
6. (Original post by georgiaaaxo)
x is greater than 3! thankyou

when i draw the graph, do i only draw the one positive line? i'm still a little confused as to how it is a reflection. the first one is a 'smiley face' quadratic right?
so how can the inverse be a reflection if you're only sketching the positives?
sorry for the questions, i missed the lesson on this topic
It would be a U-shaped parabola (i.e. a smiley face!) if the domain was R. Since you have x>0, it will only be part of the right hand side of that smiley face! Make sense?
7. (Original post by Lord of the Flies)
It would be a U-shaped parabola (i.e. a smiley face!) if the domain was R. Since you have x>0, it will only be part of the right hand side of that smiley face! Make sense?
ohhhhhhhhhhhh! yeah that makes sense. can't believe i didn't notice that aha
clearly its been a long day! thankyou so much
got it!

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