2017 Methods Exam 1 [Solutions]

[Sine]

All solutions are of exam standard and what would be required of the harshest assesor.

Estimated A+ cutoff: 36.5-37.5

NOTE: Whenever I write something like "where a =12" that is not required for full marks but is nice to put in.

EDIT: 8c should not include 0 (Zhen)

[zhen]

Just wondering why you included p=0, cause I thought that if p=0, then the probablity of A given B and B given A would be 0, cause they would be mutually exclusive events and this contradicts the given information.

[Sine]

Just wondering why you included p=0, cause I thought that if p=0, then the probablity of A given B and B given A would be 0, cause they would be mutually exclusive events and this contradicts the given information.

yeah you are right my bad. didn't check over ahah

[uhoh]

Hey Sine 😊 For the last pg, I found the gradient of AC through tan45=1. Since AC is perpendicular to BC, I found that the gradient of BC was -1. Is this correct?
Also, when I got the eqns in both c) and d), I let  root x=a and I rejected one if the solns since a has to be greater than or equal to 0. Is this right?

For Q4, when I got to your 3rd line of working, I squared both sides. I got the same ans as you at the end. Is this ok?

[Sine]

Hey Sine 😊 For the last pg, I found the gradient of AC through tan45=1. Since AC is perpendicular to BC, I found that the gradient of BC was -1. Is this correct?
Also, when I got the eqns in both c) and d), I let  root x=a and I rejected one if the solns since a has to be greater than or equal to 0. Is this right?

For Q4, when I got to your 3rd line of working, I squared both sides. I got the same ans as you at the end. Is this ok?

yes AC perpendicular to BC to find gradients is fine

not sure what you mean by your second question

for q4 if all the inequalities you wrote down were correct you are fine. The reason I don't like to do anything other than linear tranpositions (stuff like logs and exponentials) over inequalities is because it is much harder to keep track on whether i need to flip the inequality or not.

hope this helps

[plsbegentle]

jeez that's rough, an A+ cut off around 36-37. What exam score in exam 2 do i need for a 40+? I think i got 33-34/40 for exam 1.

[uhoh]

yes AC perpendicular to BC to find gradients is fine

not sure what you mean by your second question

for q4 if all the inequalities you wrote down were correct you are fine. The reason I don't like to do anything other than linear tranpositions (stuff like logs and exponentials) over inequalities is because it is much harder to keep track on whether i need to flip the inequality or not.

hope this helps

Thanks sine

I meant to say: when I got to -2root x=1-3x in a) and 2rootx=1-3x in b), I rearranged to let the rhs=0. e.g. for part a), I got 3x-2rootx-1=0. I let a=root x, so 3x=a squared and I solved the quadratic eqn.

Then, I rejected one of the solns since a has to be greater than or equal to 0 (a=rootx).

Is that ok?  

[Sine]

jeez that's rough, an A+ cut off around 36-37. What exam score in exam 2 do i need for a 40+? I think i got 33-34/40 for exam 1.

just my estimate

last year it was 34/40 and I would've predicted 35-36 so who knows ahah

Aim for 70+/80 and good sacs should secure 40+ you might be able to get away with high 60's/80

Thanks sine

I meant to say: when I got to -2root x=1-3x in a) and 2rootx=1-3x in b), I rearranged to let the rhs=0. e.g. for part a), I got 3x-2rootx-1=0. I let a=root x, so 3x=a squared and I solved the quadratic eqn.

Then, I rejected one of the solns since a has to be greater than or equal to 0 (a=rootx).

Is that ok? 

that sounds good, as long as you showed a reason for it not just randomly discarding it you are ok.

[uhoh]

just my estimate

last year it was 34/40 and I would've predicted 35-36 so who knows ahah

Aim for 70+/80 and good sacs should secure 40+ you might be able to get away with high 60's/80
that sounds good, as long as you showed a reason for it not just randomly discarding it you are ok.

Thanks again sine 😊

[thesplaaashman]

I'm still salty about that last question. Absolutely horrible...

[blehblop]

I'm still salty about that last questiom. Absolutely horrible...

same here just wanted to check if i would get marks for attempting though

9c,
I worked out M=-1 but was not able to work out C. Is this one mark?
9d,
If i simply wrote let Tangent of AC = Tangent of CB (without working out the tangents) do you guys think thats worth any marks. I also was able to conclude that the tangent of AC occurred at 1/9 and the gradient of the tangent was 1. But did not go further due to the confusion with the graph and domain of the gradient (0,1).

Also thank you so much for your help guys.

[Cyka]

Do any of yous reckon it is possible to get over a 40 is methods with a combined score across both exams of 100/120? Or even with low 30's exam 1 and high 60s-low 70s exam 2?

[joe Tadros]

question 9d
C coordinates ( 11/27 , 16/27 )

[ooft]

For question 7B i), wouldn't the answer be -1 as it's asking for the "largest possible value", and -1>-3?

[HaeIII]

Range is [0, infinity) not [1,infinity)