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Recent content by externityxzx

  1. externityxzx

    A Level Economics:

    can anyone please help me with these questions? http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Economics%20(9708)/9708_w12_qp_31.pdf Q22 -doesnt borrowing from the central bank increases the money supply in the economy...
  2. externityxzx

    A level Biology: Post your doubts here!

    http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Biology%20(9700)/9700_w12_qp_53.pdf please help with 1.(b)(i)!! im not sure what to do with the given molar mass.... thanks!!
  3. externityxzx

    A level Biology: Post your doubts here!

    http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Biology%20(9700)/9700_w12_qp_51.pdf answer: http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Biology%20(9700)/9700_w12_ms_51.pdf can anyone please explain the answer for 1...
  4. externityxzx

    How was Biology Paper 42

    thats the question i did :) i found that neurone question confusing.... for (a) i wrote that the resting potential is maintained by the sodium potassium pump.... since that stops, ions will diffuse down their electrochemical gradient into the cell (from -40mV to +0mV ). is that correct though...
  5. externityxzx

    A level Biology: Post your doubts here!

    can anyone explain how does superovulation occur?? what hormones and drugs are used and what are their effects? how does it allow many follicles to form?
  6. externityxzx

    A level Biology: Post your doubts here!

    oohhhh i see!! thanks!!!!! :)
  7. externityxzx

    A level Biology: Post your doubts here!

    im still confused... what is high silica content?
  8. externityxzx

    A level Biology: Post your doubts here!

    can anyone please explain this one adaption of sorghum in arid conditions? i cant find it in the book :o much thxx!! high silica content / more sclerenchyma / more strengthening tissue - reduces wilting
  9. externityxzx

    Mathematics: Post your doubts here!

    you can substitute 3x to something else like y (anything) so 3x = y so you have tan y =-2, you have to change the range 0<x<180 to 0<y(which is 3x)<540 then you have y= -63.4 + 180 (keep adding 180) y2= 116.6 and you put it back into y =3x which gives you 38.9 y3= 296.6 => 98.9 y4=476.6 => 158.9 :)
  10. externityxzx

    Mathematics: Post your doubts here!

    can anybody please explain how you put work done, work done against resistance, PE gain/loss, KE gain/loss in an equation? im lost :((( thank you!!
  11. externityxzx

    Mathematics: Post your doubts here!

    this is how i did it (i)let PN= y the triangle PTN is equal to tanx so 0.5x(y x TN)= tanx TN=2tanx/y dy/dx = y/ (2tanx/y) =y x y/2(sinx/cosx) =y^2 x 1/2(cosx/sinx) =1/2 y^2 cotx (ii) dy/dx =y^2/2 x cosx/sinx 2/y^2 dy= cosx/sinx dx (integrate this) -2y^-1 =ln(sinx) +c apply y=2 x=1/6 pi...
  12. externityxzx

    Mathematics: Post your doubts here!

    move the right part to the left side secx-(3-1/2x^2) x=1 => -0.649 x=1.4 => 3.863
  13. externityxzx

    Mathematics: Post your doubts here!

    http://papers.xtremepapers.com/CIE/Cambridge%20International%20A%20and%20AS%20Level/Mathematics%20(9709)/9709_s09_qp_3.pdf please help me with Q6. (ii) & (iii) i don't understand the question vectors-9. (i) (ii) and intergration-10. (ii) (iii) Thanks!!!
  14. externityxzx

    biology paper 1 doubts

    wow... i never realized that!! thank you!!
  15. externityxzx

    biology paper 1 doubts

    7 What is the theoretical number of chemically different dipeptides that may be assembled from 12 different types of amino acids? A 24 B 72 C 144 D 400 This is what i did 2 x 12 x 3=72 but the answer is C.... can anyone please explain this to me?
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