IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => GCE AS & A2 Level => Math => Topic started by: DEGO on April 14, 2010, 08:16:12 pm

Title: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: DEGO on April 14, 2010, 08:16:12 pm: A PARTICLE MOVES ALONG A LINE
for> the distance of particle from O at time T is X meters WHERE
x=20/t

find an expression for the acceleration of the particle
i cant understand how its answered in MS
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: astarmathsandphysics on April 14, 2010, 08:20:04 pm: Write it as $x=20*t^{-1}$ and diffentiatte
$v=\frac {dx}{dt} =-1*20*t^{-2} =-20*t^{-2}$
$a=\frac {d^2 x}{dt^2} =-2*-20*t^{-2} =40*t^{-3}$
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: DEGO on April 14, 2010, 08:23:59 pm: how did the 20 change to - 20 XD (some times i get mind block)
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: holtadit on April 14, 2010, 08:29:10 pm: Dude this isnt IGCSE man !!

This is like A-Level
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: DEGO on April 14, 2010, 08:42:04 pm: i got it THX (the first hard question i meat in edexel maths)
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: Amr Fouad on April 14, 2010, 08:56:24 pm: this is not IGCSE..it's A-L
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: DEGO on April 14, 2010, 09:07:31 pm: i solved it in olvl maths edexel
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: astarmathsandphysics on April 14, 2010, 09:09:38 pm: I edited my post above
When you differentiate Multiply by the power then take 1 from the power
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: halosh92 on April 14, 2010, 09:33:00 pm: Quote from: DEGO on April 14, 2010, 08:16:12 pm
A PARTICLE MOVES ALONG A LINE
for> the distance of particle from O at time T is X meters WHERE
x=20/t

find an expression for the acceleration of the particle
i cant understand how its answered in MS
is this AS or Alevel which paper is it from?
Title: Re: HELLP ME ON THIS QUESTION OF MATHS PLSSSSS
Post by: DEGO on April 15, 2010, 02:53:16 pm: i found it paper 4h edexel i am olvl idk if its Al cambridge