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AQA C4 Differential Equations

hello, can someone help me with this question please?
I've attached both the question and what I've done so far.. I am stuck!
(edited 9 years ago)
It isn't e^t + e^c that line is incorrect
It would be e^(t+c)

However
I would suggest keeping the k with the dt at that makes life easier
Original post by TenOfThem
It isn't e^t + e^c that line is incorrect
It would be e^(t+c)

However
I would suggest keeping the k with the dt at that makes life easier


Ok, so I've done this now. What shall I do?
Original post by chococup123
Ok, so I've done this now. What shall I do?


You were told that x is zero at the start .. Find c
t= 0, x=0.... find c
Original post by TenOfThem
You were told that x is zero at the start .. Find c


is C = ln(1/60) ?
Original post by the bear
t= 0, x=0.... find c


Is C = ln(1/60) ??
Original post by chococup123
is C = ln(1/60) ?


Yes
Original post by TenOfThem
Yes


Oh I got it, thank you very much! What about part b)? what have I done wrong?

edit: no worries, I've worked out part b) now. I just need help starting c?
(edited 9 years ago)
Original post by chococup123
Is C = ln(1/60) ??


yes :borat:
Original post by the bear
yes :borat:


Thank you, What have I done wrong with part b?
Because it doesn't seem wrong to me haha

edit: no worries, I've worked out part b) now. I just need help starting c?
(edited 9 years ago)
Original post by chococup123
Oh I got it, thank you very much! What about part b)? what have I done wrong?

edit: no worries, I've worked out part b) now. I just need help starting c?


Have you put time = 3 hours into your equation?
Original post by TenOfThem
Have you put time = 3 hours into your equation?


the equation from part b?
Original post by chococup123
the equation from part b?


Yes
Original post by TenOfThem
Yes


Yes, I have. Do I have to work out k before?

Edit: I got x to be 55.5, is that correct?
(edited 9 years ago)
Original post by chococup123
Yes, I have. Do I have to work out k before?

Edit: I got x to be 55.5, is that correct?


No idea but it is less than 57 so it looks good
Original post by TenOfThem
No idea but it is less than 57 so it looks good


Aww thank you very much for your help!

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