Recent content by lxyinnet

  1. L

    Math

    tan x = sin x / cos x , sub. it into equation, then cos ^2 x = 1/2 , x= 45 + n90, n is an integer.
  2. L

    Urgent IGCSE chemistry revision guide needed

    I have this version only.
  3. L

    HeIp post

    Here U are!
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