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Edexcel M4 Exam Discussion Thread [June 5th]

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For the second order DE in number 5, when we had to find C and D etc. Finding C was trivial (t=0, x=0), but when you differentiate to find D, when t=0 does dx/dt=0? I had that originally, but if B is moving at 1/4sin2t, isn't dx/dt 1/2cos2t, ie 1/2? 0 or 1/2?
Original post by NathanSE
crap I found when x is 0 : P, do you know how mnay marks that part was?


5 I think
Original post by NathanSE
crap I found when x is 0 : P, do you know how mnay marks that part was?


you have just boosted gome's ums well done. he is probably laughing at you thinking how dumb you are... those were 'gift marks' mate.
Original post by Gome44
70 for an A* maybe. The only tricky part was the stability question, but there was a similar one in the review exercise I think


Mate the stability question was the easiest thing I have ever seen. bad luck.... you may get an a1 ft. and scrape the A* congrats!
Reply 184
Jabber jabber. Put the kettle on, make some tea, grab some pen and paper and listen in. cos4t=cos2t simplifies to (4cos^2(t)+1)(cos^2(t)-1)=0 ......now take a sip of your tea, taste that? That's the taste of failure.



Original post by shan2097
yes it was pi/3. x in terms of t should have been 1/6 sin 2t - 1/12 sin 4t, therefore dx/dt = 1/3 cos 2t - 1/3 cos 4t. dx/dt = 0 at instantenous rest therefore cos 2t = cos 4t. 2t = 2kπ +- 4t. at first instantaneous rest k = 1 therefore t = π - 2t 3t = π t = π/3
Original post by User1206819
Mate the stability question was the easiest thing I have ever seen. bad luck.... you may get an a1 ft. and scrape the A* congrats!


Someone's mad...
Original post by Gome44
:yy:


wow is this all you have got? have you told your mom how well you did in m4 yet???
Original post by Gallax
Jabber jabber. Put the kettle on, make some tea, grab some pen and paper and listen in. cos4t=cos2t simplifies to (4cos^2(t)+1)(cos^2(t)-1)=0 ......now take a sip of your tea, taste that? That's the taste of failure.


Sub in x=2 radians and you'll see that isn't the case...
Original post by c3l6founder
wow is this all you have got? have you told your mom how well you did in m4 yet???


I have actually :smile:
What did the rest of you guys get for questions 3 and 4? I seem to have got different answers than the ones posted earlier :s-smilie:
Original post by bigblackterence
What did the rest of you guys get for questions 3 and 4? I seem to have got different answers than the ones posted earlier :s-smilie:


Tel


Posted from TSR Mobile
my answers were

Spoiler

Lol why is everyone being dicks to each other. Everyone here is pretty smart, if you got something wrong chill it's Ayg


Posted from TSR Mobile


Gurbs
Original post by c3l6founder
you have just boosted gome's ums well done. he is probably laughing at you thinking how dumb you are... those were 'gift marks' mate.

Even if he were I dont care if Gome or anyone else laughs at me because im not a self conscious wreck that cant handle othere people being better at m4 than me.
Original post by c3l6founder
you have just boosted gome's ums well done. he is probably laughing at you thinking how dumb you are... those were 'gift marks' mate.


Never said they were gift marks. Question 1 was (pretty much identical to last years question one), and question 2 was one of the easiest RM question they could have asked...
Original post by Gallax
Jabber jabber. Put the kettle on, make some tea, grab some pen and paper and listen in. cos4t=cos2t simplifies to (4cos^2(t)+1)(cos^2(t)-1)=0 ......now take a sip of your tea, taste that? That's the taste of failure.


bugger it, missed 1/sqrt(2) didn't I. Should've expanded and checked. oh well. Only a coupla marks.

edit: no hang on. pi/4 doesn't work because cos pi = -1 and cos pi/2 = 0
(edited 8 years ago)
Original post by NathanSE
Even if he were I dont care if Gome or anyone else laughs at me because im not a self conscious wreck that cant handle othere people being better at m4 than me.


then what are you doing on student room? you clearly care so much abt what you got in m4 that u came here straight after the exam.
Original post by c3l6founder
then what are you doing on student room? you clearly care so much abt what you got in m4 that u came here straight after the exam.


because I want to know what grade I got. I care about doing well in m4 but i dont care that other people do better than me.
So can i Assume that 68/75 will be an 90UMS ?

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