Edexcel IAL Mathematics C34- 17th January, 2017

I didn't have time to calculate exact time with pm, but time was 22.5 hours

EDIT: that question was confusing, what was your lambda?

Whaat? I got 6.4 hours I can't remember what Ii got for lambda tho

8/15?

I didn't get that Do you remember the question so we can re-do it?

Yes.

First part stated at time 4 pm there was no ice.
At time 6pm there was 1.5mm of ice (x). Rate of increase of the thickness of ice was constant, meaning dx/dt = k.

Find t in terms of x.
I got t=4x/3

part b was dx/dt = Lambda/(2x+1)

i) find t in terms of x and lambda
ii) calculate lambda
iii)calculate t when x=3.

As far as I can recall this was the whole question

Were there any new ideas introduced? Or was it the same as all the previous years?

Wow you have a very good memory. I got 15/8 as lambda...

integration is:
x^2 + x = (lambda)*t +C
C is zero after subbing in t=0 and x=0 (at time 4pm)
then, lambda= (x^2 + x)/t and subbing in t=2 and x=1.5 (at time 6pm) we get lambda as 15/8
then, t=(x^2 + x)/(15/8)
subbing in x=3, t=(9+3)/(15/8)=6.4 hours
which is equivalent to 6 hours and 24 minutes hence the time would be 10:24pm.... I guess this is correct

Wow you have a very good memory. I got 15/8 as lambda...

integration is:
x^2 + x = (lambda)*t +C
C is zero after subbing in t=0 and x=0 (at time 4pm)
then, lambda= (x^2 + x)/t and subbing in t=2 and x=1.5 (at time 6pm) we get lambda as 15/8
then, t=(x^2 + x)/(15/8)
subbing in x=3, t=(9+3)/(15/8)=6.4 hours
which is equivalent to 6 hours and 24 minutes hence the time would be 10:24pm.... I guess this is correct

Yeah I guess you are right, I couldn't figure out this question till the very end because part b specifically stated a "Second model" has equation etc etc so I tried to work on it with only what was given in part b.
Tried to rush through the question and I guess I got wrong lambda :/

What was your area of parallelogram? I got 36(underroot2)

Ok ok dw im sure you did the other questions well, I actually didnt see the 14th question so I was doing the 13th question slowly and casually and I just flipped the page and when I saw it lmao I managed to do all the parts in time except for the last two mark one(my brain wasn't functioning).

I had it in the bag, only after I got out of the exam hall with a smiling face thinking I am getting an a* that I realised I didn't see any vectors question, which was weird. And then a stranger told me vectors came, it was the last one. No. 14. No.14????? There was a no. 14???? Fml

I can't remember I didn't know what to do so I found the shortest perpendicular distance from point A to the line CD and multiplied by CD legnth

I had it in the bag, only after I got out of the exam hall with a smiling face thinking I am getting an a* that I realised I didn't see any vectors question, which was weird. And then a stranger told me vectors came, it was the last one. No. 14. No.14????? There was a no. 14???? Fml

Wow you have a very good memory. I got 15/8 as lambda...

integration is:
x^2 + x = (lambda)*t +C
C is zero after subbing in t=0 and x=0 (at time 4pm)
then, lambda= (x^2 + x)/t and subbing in t=2 and x=1.5 (at time 6pm) we get lambda as 15/8
then, t=(x^2 + x)/(15/8)
subbing in x=3, t=(9+3)/(15/8)=6.4 hours
which is equivalent to 6 hours and 24 minutes hence the time would be 10:24pm.... I guess this is correct

I got the same answer, 6.4 hours. Though my method was a bit different, I substituted in t=2 and x=1.5 instead of x=0 when t=0. Can't remember my lambda value.