2017 HSC Mathematics Paper thoughts (1 Viewer)

[Eluate]

I think I chose 2 because you count how many times it goes from positive to negative or negative to positive. But I think might have misread the graph, not sure lmao

Well if its velocity, does it not mean that when its below the graph its just moving in the same direction but alternates speed?

 

[1729]

yayy u got it right haha. its cos the top half is the positive direction and vice versa. the stationary points only highlight a change in speed i.e. like it slowed down more

No it's 1. It stops at first but doesn't change direction.

Yeah that’s right. Also, if the particle only touches the x-axis, does that count as a change in direction?

assuming t-axis, then no, it just stops at that instant.

 

[katasenpai]

No it's 1. It stops at first but doesn't change direction.



assuming t-axis, then no, it just stops at that instant.

Yeh, that's what I realised just now, misread it

 

[1729]

Did people actually solve that dL/dx = 0 equation? I just used similar triangles, was much faster.

 

[portia1605]

yeah i got 1.

 

[sandybay]

I walked out not realising I could take the paper. Can someone please scan and post for us

 

[Georgiiaa]

Yeah I did, it actually didn't take that long.

there were a lot of numbers but it was rather ok

 

[1729]

there were a lot of numbers but it was rather ok

3.75?

 

[AT]

Whats everyone reckon the raw mark cut offs for Band 5/6 going to be?

 

[katasenpai]

I got 3.75. You just equated sina and sinb right? x/5 = 9-x/7 ??

 

[1729]

Will they accept both 880 and 870? Exact k gives 870, but rounded gives 880.

 

[Georgiiaa]

no i mean in L with the square roots

 

[1729]

I got 3.75. You just equated sina and sinb right? x/5 = 9-x/7 ??

I proved similarity because a = b and the right angles, so you get the proportion x/5 = (9-x)/7

 

[Seisaka]

I mistakenly thought that was a position function so i chose 3

 

[PARLIAMO314159]

x=15/4=3.75

 

[katasenpai]

I did it by using the actual distances given in part i) and got 3.75. L had a minimum value of 15 from memory?

Wait, did you have to find the minimum L value???

 

[Jaaames007]

Did we get x=36 degrees for the parallel lines question

 

[PARLIAMO314159]

No, you just had to show that x=3.75 was a minimum through either showing d^2y/dx^2>0, or through showing the gradient was <0 for values <3.75, and >0 for values greater 3.75.

 

[PARLIAMO314159]

Yep

 

[1729]

Wait, did you have to find the minimum L value???

No, it asked for x such that sina = sinb then asked to explain why it gives a minimum value of L.