Page 1 of 1
Stationary point of s(t)=t lnt (Maths).
Posted: Wed Apr 09, 2008 9:51 pm
by _Imwashingmypirate
Hey I am working on a question and am stuck. I differentiates the equation in the title to get; lnt +1
lnt+1=0 (For stationary points).
e^(lnt) = e^(-1)
t=1/e
I now want to find y. I put this back into the equation...
y = 1/e ln (1/e)
Do I put these together to get, y = ln/e^2 Or am I on another planet. How do I find y?
Thanks,
Posted: Wed Apr 09, 2008 9:54 pm
by _Imwashingmypirate
Or do I use product rule? If so then do I take t = u, ln = v and t=w?
Posted: Thu Apr 10, 2008 4:58 pm
by _Dr. Shades
You do both.
Posted: Fri Apr 11, 2008 12:18 am
by _Imwashingmypirate
Erm Ok. Thanks.
Posted: Fri Apr 11, 2008 5:55 pm
by _Imwashingmypirate
Actually it's all wrong above. I worked it out.
Posted: Fri Apr 11, 2008 10:19 pm
by _asbestosman
Imwashingmypirate wrote:Actually it's all wrong above. I worked it out.
t=e ?
proof:
t = s(t)
t = t *ln(t)
1 = ln(t)
e^1 = t
Posted: Sat Apr 12, 2008 12:49 am
by _Imwashingmypirate
t = 1/e any s = -1/t
Proof
s(t)=t lnt
s' = lnt +1
lnt+1=0 (For stationary points).
lnt = -1
e^(lnt) = e^(-1)
t=1/e
I now want to find y. I put this back into the equation...
y = tlnt
t = 1/e
lnt = -1 from above.
therefore tlnt = -1/e
thus s = -1/e
Resulting in the stationary point of s(t)=tlnt, being (1/e, -1/e)