WMA14 01 IAL (Edexcel) P4 Oct 2021 Q9 Forming & Solving Differential Equations

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[@amrahmedhesham8587]

hello sir do you give tuitions for s1

[@stevenithoughtyouweredead]

Why multiply by 20 in a?

[@javedfaizal5473]

the question requires you to show it in the given form so the only way to reach that is by multiplying by 20

[@baraaadnan7090]

sir will he give me the volume and area formulas in the data booklet
and if not what are the shapes that I should know how to calculate their volumes and areas

[@MrHassaansMathsChannel]

in general the question will give you surface areas of cones or spheres but prisms they won't be given, so things like cylinders and triangular prisms for example

[@yudumazizoglu2552]

Why did we say dv/dt instead of dh/dt as the height changes or why didnt we say dr/dt as it says constant rate in a)

[@MrHassaansMathsChannel]

because they gave us a a value for the rate of change in Volume.. thats what they gave us the value of

[@MrHassaansMathsChannel]

try to listen carefully to what i explain because i mention it clearly why we use it

[@yudumazizoglu2552]

@@MrHassaansMathsChannel thank u

[@sharif7418]

Sir i have a question, is is usefull to do past questions from papers before 2010

[@MrHassaansMathsChannel]

Yes of course it is... the more practice the better

[@yutosagara9104]

As long as the answer for b is 208 minutes round up , my answer also correct right ? It was t=320/3*lin(7)

[@rohanmartin5743]

Hi sir, why do you sometimes factor out a value from the integral? for example, I factored out 1/3 from the integral of 1/12-3h(dh) to give me 1/3 times the integral of 1/4-h(dh)? This led to me getting the wrong answer. Can u explain when and when not to do this. Thank you for the videos.

[@mar.washere]

hey there - i tried it by factorising 1/3 out and got the exact same answer - it's not wrong. you must have messed up somewhere else - check the ms and look at the variations of the answer, it's in there! you will get a different +c value but the final t will be the same.