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Recent content by mathsbrain

  1. M

    pls help

    Question: Sugar is dissolved in water in the ratio 1:3 to form sugar syrup. This sugar syrup is further diluted with the addition of water so that the ratio of the sugar syrup to the additional water is 5:7. FInd the ratio of sugar to water in the final mixture.
  2. M

    AMC practice

    Hi can anyone explain the following? Two identical coins are placed one inside and one outside a thin circular wire, which has twice the diameter of each coin. Each coin is rolled, without slipping, around the wire until it returns to its starting point. If the direction of rotation does not...
  3. M

    parametrics question

    Umm if you try expanding and simplifying don't you get 0=0 which is saying we havent found a catesian relation?
  4. M

    parametrics question

    Hi, Stuck on this question: convert x=tanx-sinx and y=tanx+sinx to cartesian form. Thanks!
  5. M

    sketching reciprocal function

    Thanks, but just a little confused regarding point 1), you mentioned x=/=0, so why is that a closed circle then?
  6. M

    sketching reciprocal function

    Hi, 1) Just wondering what happens when you reciprocate a vertical asymptote. For example if you are given the graph y=1/x and asked to reciprocate it, will the origin be an open circle or closed circle. 2) If you are NOT given the equation of y=1/x but given something that looks similar...
  7. M

    2U Maths Exam Thoughts

    How come the Ngo and Sons have made solutions already? I thought coaching colleges can't access these papers since they are copyrighted by NESA?
  8. M

    BOS trial

    Thanks for the fun!
  9. M

    BOS trial

    what? is that banned?
  10. M

    BoS Maths Trials 2017

    Hi will there be a 2018 version?
  11. M

    BOS trial

    Was stuck on a question: Sketch the locus defined by arg(z^2+z)=pi/3, stating its equation. Obviously this will turn into the hyperbola with the positive branch, but how do we find the equation? Also, anyone know when the bored of studies trial will be held this year, of is it held already...
  12. M

    function notation

    Hi, A bit confused with the use of the notation y=f(x). If we have the circle x^2+y^2=1, we can obviously rearrange and make y the subject which gives y=+-(1-x^2)^0.5. Is it wrong to write f(x)=+-(1-x^2)^0.5 since this is not a function hence we can't use f(x)? If so, does that also mean...
  13. M

    integration by substitution

    Consider the integral of sin(2x+1). I note the normal method would be to let u=2x+1(if you are asked to use substitution). But can someone explain the following method: integral (sin(2x+1)dx)=integral(sin(2x+1) d(2x+1)/2)?
  14. M

    BOS 2017 paper

    anyone know if this is coming T_T
  15. M

    BOS 2017 paper

    oh dear...so anyone else going to make a paper to sit?