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[CIE] All Pure Mathematics (P1, P2 and P3) doubts here !

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elemis:

--- Quote from: physichemaths on May 02, 2011, 11:08:49 pm ---help me with question j08 question8? anyone?

--- End quote ---

Since the area of the triangle equals to tanx  :

0.5*TN*PN = tanx

This can be re-written as :

0.5*x*y = tanx

The gradient of the tangent is simply :

dy/dx  = y/x

Finding the reciprocal of both sides :

dx/dy = x/y   

Re-arranging :

y*dx/dy = x

Substituting into original equation :

0.5*y2*dx/dy = tanx

Moving everything around :

0.5*y2*dx/tanx = dy

0.5*y2*dx*cotx = dy

0.5*y2*cotx = dy/dx

Done !

SkyPilotage:

--- Quote from: ~~!$!HUSH!$!~~ on May 03, 2011, 05:30:14 am ---MJ 2010 P13,Q6 part 1,i did AB.BC but in the MS it was AB.CB,how do u know which order do u use?


--- End quote ---
Pretty Simple,
When they ask for angle ABC you either do BA.BC  or AB.CB
You just have to either go from inside to outside or outside to inside.
More ex: -Angle DAC You either do DA.CA or AD.AC
Ofcourse you have to use the corresponding modulus of each!
             -Angle PQR You can use QP.QR or PQ.RQ
Hope it clears things up :)

HUSH1994:
Thanks alot,i thought if ABC then AB.BC,thanks and a +rep for you :)

Arthur Bon Zavi:
Have a look at some other papers (paper 1 of p1) to have your doubts fully cleared.

By the way, VECTORS was a cakewalk for you. ::)

HUSH1994:
i know,tbh all the pure is a piece of cake,but there are always some questions that need thinking,i got 69/75 in this papers and i finished it in 1hour 10 mins,my biggest problem is signs,esp in binomial series :S

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