Methods Exam 2: Discussion!

[Orb]

For Question 2, would a mark be lost for not having absolute values in the log function? I.e. ln(2x-1) without absolute values.

Obviously with these numbers it worked without the absolute values, but I know to be entirely correct it needs the absolute value, would I lose a mark for it though?

Thanks

Yes, unfortunately :/

[keltingmeith]

For Question 2, would a mark be lost for not having absolute values in the log function? I.e. ln(2x-1) without absolute values.

Obviously with these numbers it worked without the absolute values, but I know to be entirely correct it needs the absolute value, would I lose a mark for it though?

Thanks

Actually, I don't think you would - an examiner could just interpret that as you knowing which side of the log you wanted, and actually call it genius instead of a silly mistake.

[Orb]

Actually, I don't think you would - an examiner could just interpret that as you knowing which side of the log you wanted, and actually call it genius instead of a silly mistake.

Wouldn't that be leaving it down to a bit of luck?

[M_BONG]

Yeah, I remember assessor report once said you get a mark taken off if you don't put absolute values when integrating into logs, even if you are sure they are positive. :S - you only remove the abs sign once you are certain it's positive - ie. you wouldn't write ln|5|.

But marking scheme changes every year, I guess.

[keltingmeith]

Wouldn't that be leaving it down to a bit of luck?

Oh, absolutely! But the mark could stay there.

Yeah, I remember assessor report once said you get a mark taken off if you don't put absolute values when integrating into logs, even if you are sure they are positive. :S - you only remove the abs sign once you are certain it's positive - ie. you wouldn't write ln|5|.

But marking scheme changes every year, I guess.

See, I read that, but only interpreted it for the indefinite integral... In fact, if they ask for an antiderivative, you would be more right if you didn't include the modulus signs (although I'm sure VCAA would take off marks if you did that)

[de]

Hi,
Does anyone else think that MC Question 14 was kind of wrong because it didn't state that the distribution was discrete. You had to assume that Pr(X=5) was 0. Otherwise options were wrong. I find it amazing that it din't state continuity.

[potahto]

i had no idea what they meant by 'fraction of time'!!!! *derp*
do you think i'll lose a mark if i just wrote 4 months???

[de]

i had no idea what they meant by 'fraction of time'!!!! *derp*
do you think i'll lose a mark if i just wrote 4 months???

So sorry, but yes. You didn't answer the question. There will be quite a few people who did the same I suspect.

[Orb]

i had no idea what they meant by 'fraction of time'!!!! *derp*
do you think i'll lose a mark if i just wrote 4 months???

In scenarios like this, it would be a lot safer if you wrote 4 months = 1/3 in fraction terms or something like that :/

[potahto]

So sorry, but yes. You didn't answer the question. There will be quite a few people who did the same I suspect.

aw damn
also it should be fine if the generic expression for the tangent wasn't simplified and expressed in the form y=mx+c right? cuz they never asked for it...

[suberman123]

Hi,
For the probability question 4 a (1 mark) and d (2 marks) I mistakenly multiplied by 1000 when converting to millimeter. Other calculations are correct. Does it completely take 2 marks away?

[de]

also it should be fine if the generic expression for the tangent wasn't simplified and expressed in the form y=mx+c right? cuz they never asked for it...

Yes that is fine.

[de]

Hi,
For the probability question 4 a (1 mark) and d (2 marks) I mistakenly multiplied by 1000 when converting to millimeter. Other calculations are correct. Does it completely take 2 marks away?

I'd say so. Although they ***might*** take the first mark and then say "taken off earlier". I got that in a sac.

[DanielJ]

i had no idea what they meant by 'fraction of time'!!!! *derp*
do you think i'll lose a mark if i just wrote 4 months???

Atleast you didn't think there were 24 hours in half a day.. did 4/24 =1/6

[Lauren101]

Last question was a bit hard.....