Join in on the Guess The Rep Game #6 !! >>

Edexcel A-level Politics post exam chat here >>

Edexcel A-level Further Maths post exam chat >>

Big moments and top student reactions from GCSE English Literature Paper 2 >>

Check our round-up to see how students reacted to GCSE Chemistry Paper 1 >>

Join in on the Guess The Rep Game #6 !! >>

Edexcel A-level Politics post exam chat here >>

This discussion is now closed.

Check out other Related discussions

C4 Differentiation

Can anyone help me answer this

Setting up differential equations from information given in a context:

In a pond the amount of pondweed (P) grows at a rate proportional to the amount of pondweed already present in the pond. Pondweed is also removed by fish eating it at a constant rate of Q per unit time.

Write down a differential equation relating P and t where t is the time which has elapsed since the start of the observation.

Reply 1

If you let P = amount of pondweed already present, they tell you it grows at a rate proportional to P. Rate implies dP/dt, proportional implies direct proportionality (i.e. k*variable).

Reply 2

from the first point, dP/dt= kP
from the second dP/dt= -Q
both are occuring at once, so dP/dt= kP -Q ...

Reply 3

OP

thnx for all the help

Latest

Trending

Articles for you

Bmat: when it is, what it costs and how to prepare

Bmat: when it is, what it costs and how to prepare

$What is LaTeX?$

What is LaTeX?

Edexcel A-Level Economics Paper 1 - Unofficial Mark Scheme - 18 May 2023

Try out the app

Continue on web