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  1. J

    calculating pH

    \noindent $Degree of Ionisation $ = \frac{[H^+]}{[HA]}\times 100 \% \\ \\ $Where $ HA $ is the intact acid molecule $ \\ \\ \therefore 0.5 = \frac{[H^+]}{0.05} \Leftrightarrow [H^+]=0.025 \\ \\ $ pH $ = -\log [H^+]\\ = -\log 0.025 \\ = 1.6 it basically means that only 50% of all acid...
  2. J

    Can someone please check where I made a mistake 20b only please

    between your 6th last and 5th last step log(a+b) =/= log(a)+log(b) ie, you cant expand it like a normal algebraic term, its like how you cant expand sin(a+b) into sin(a)+sin(b) so continuing, ln(8+√48)-ln4 = ln(8+4√3)-ln4 =ln((8+4√3)/4) =ln(2+√3)
  3. J

    finding TDS

    TDS is found by evaporation to dryness so the solid remaining in the basic after evaporation is the mass of the TDS, which is 44.67-43.53 = 1.14 now to find the percentage, divide this by 250 mLs and times it by 100 = 0.46% (to 2sf)
  4. J

    Post your 2017 ATAR below!

    99.55 Rip english
  5. J

    2017 HSC Marks Prediction Thread

    Re: 2017 HSC Marks Thread 4u: 97 3u:99 Eng adv: 86 Chem: 94 Phys: 93
  6. J

    Estimate own atar

    Can you guys pls shout me lunch if I get <99.95 thanks :)
  7. J

    Estimate own atar

    interesting
  8. J

    2012 MC HSC Exam question help

    https://imgur.com/a/BAU45 oops pls ignore the negative signs
  9. J

    2017 Mathematics Extension 1 HSC Exam Thoughts

    Really straightforward tbh
  10. J

    complex numbers query

    for complex number z=a+ib, arg(z) = arctan(b/a) [-pi < arg(z) ≤ pi] and its clear that 5-5i is in the 4th quadrant, so the argument of 5-5i is arctan(-1) = -pi/4
  11. J

    Cambridge Complex Numbers Question

    \noindent $Modulus of $iz = |iz| = |i| \cdot |z| = r \\ ($as the modulus of i is 1 and z is r$) \\ $Argument of $iz = \arg (iz) = \arg (i)+ \arg(z) = \theta + \frac{\pi}{2} \\ $ (as the argument of i is $\frac{\pi}{2} $and z is theta$) if you havent learnt the above stuff, then let z = a+ib...
  12. J

    English Paper 1 - Thoughts

    haha dont worry, im sure atleast half the people did the same thing (ie bs it to the max)
  13. J

    2017ers Chit-Chat Thread

    Good luck my bos fam :') We'll all hopefully smash it
  14. J

    VCE Maths questions help

    if you want the exact value of x; take the log of both sides to get log(2^x)=log(7) now apply the rule log(a^b)=blog(a) on the LHS to get xlog(2)=log(7) hence x=log(7)/log(2) put this on the calc if you want an approximation
  15. J

    HSC 2017 MX1 Marathon

    here's a pree cool nested root integral to try out; \noindent $ Evaluate $\int_{2}^{12}\sqrt{x+\sqrt{x+\sqrt{x+...}}}$ d$x
  16. J

    HSC 2017 Predictions Thread [MX1]

    I guess so cause that's the only induction q in that paper haha
  17. J

    HSC 2017 Predictions Thread [MX2]

    I really hope there are qs on proving some interesting results, like the Basel problem from 2010 Circle geo is fine too, but yeah probability = gg
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