Quick Past HSC Q (1 Viewer)

[mreditor16]

Quick Q (especially looking for an answer from someone as experienced as Carret or Trebla):



for f), if I say the graph passes the horizontal line test, and draw a horizontal line on my graph in e), is that enough to get the mark? what do I need to say to guarantee the mark?? :O

Thanksssss

 

[seventhroot]

you sketched the curve in e) so say it does that should be good enough

also mention that f'(x) > 0 so hence has an inverse function

 

[faisalabdul16]

I think for 1 mark it should be fine.

Is this 3u?

 

[mreditor16]

I think for 1 mark it should be fine.

Is this 3u?

Yes, 1995

 

[Carrotsticks]

wooo I did this this morning
I think saying its a one-one function in the given domain (i.e. one x value for every y-value) will suffice for a mark

Saying that alone is not enough.

You will have needed to refer to the diagram, OR your 1st derivative (and then state/explain that it is always positive).

 

[mreditor16]

Saying that alone is not enough.

You will have needed to refer to the diagram, OR your 1st derivative (and then state/explain that it is always positive).

so is what I said originally enough??

 

[Carrotsticks]

so is what I said originally enough??

Yes, but cutting it close.

To be safe, also add something like "each fixed Y value --> 1 unique x value, so when we draw the inverse, each X value --> unique Y value ie: f inverse is a function."

 

[mreditor16]

Yes.

Thanks Carret!

 

[Carrotsticks]

Haha I saw that =p

But yes that is fine.