The Student Room Group
Reply 1
Try putting N(t) = 0, and see if you can find a value of t that fits.
Reply 2
i said (ii) not (iii)
which math subject is this...yikes
Reply 4
batman_
Which gives:N(t)  =  3000e(ln(3)3)tN(t) \;=\;3000e^{(\frac{ln(3)}{3})t}...............................(=  30003t3)(=\;3000\cdot3^{\frac{t}{3}})

Without looking at all the question, this is clearly wrong. e(13ln(3))t=et.eln(313)=313ete^{(\frac{1}{3}\ln(3))t}=e^t.e^{\ln(3^{\frac{1}{3}})}=3^{\frac{1}{3}}e^t


edit: Having looked at the question, I agree with your answer for i) and that N(t)=3000×313et3000\times 3^{\frac{1}{3}}e^t

The equation for ii) is the first one you said but with a slight difference... You have N(t)=3000×313et4500(t3)N(t)=3000\times 3^{\frac{1}{3}}e^t-4500(t-3)(only valid for t>3) Do you see why?
Reply 5
nota bene
The equation for ii) is the first one you said but with a slight difference... You have N(t)=3000×313et4500(t3)N(t)=3000\times 3^{\frac{1}{3}}e^t-4500(t-3)(only valid for t>3) Do you see why?

Not really, why is there a (t-3)?
(I was beginning to to think the 3rd was right...)

edit: Having looked at the question, I agree with your answer for i) and that N(t)=3000×313et3000\times 3^{\frac{1}{3}}e^t

you wrote that not me, unless u meant N(t)=  30003t3N(t)=\;3000\cdot3^{\frac{t}{3}}

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