Inverse Functions question.

[imanmalik]

F(x) = 2x+1
f(g)= x^2 - 2

find an expression for
f-1 g(x)

so the inverse of f is y=2x+1 -> (y-1)/2 =x -> y= (x-1)/2
then you punch in the value of g ((x^2 - 2)-1)/2=y
(x^2 - 3)/2 = f-1g(x)

but the mark scheme says F-1(x)= 1/(2(x-1) and f-1g(x) = 1/(2(x^2 - 3))

How?

 

[CaptainDanger]

Marking scheme is wrong there... Check the answer in examiner report... It is same as yours...

 

[imanmalik]

Marking scheme is wrong there... Check the answer in examiner report... It is same as yours...

thank you so much...i was like...HOW THE HELL CAN I GET SUCH AN EASY QUESTION WRONG xD

 

[Abeer Hatecrew]

My teacher even got freaked out by that -.- !!! Stupid mark scheme!!!

 

[midhat_moon]

how can they get the mark schemes wrong, mark schemes are the one thing we students are so dependent on!

 

[CaptainDanger]

Even papers have miss prints... They are humans too...

 

[Abeer Hatecrew]

True but they should re-check and confirm these stuff are not wrong! Who knws a simple printing mistake can ruin someones life

 

[midhat_moon]

i soo agree with Abeer, dude c'mon, i dont think these M.S are only assigned to one person to complete and post, i think there are a lot of people who do or at least should review them....

 

[no.mercy]

The marking scheme seems to have a mistake here, your methodology is totally correct.