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  1. L

    Can I discontinue a course before Honours year?

    A degree without Honours is referred to as a "pass" degree. If you don't do the Honours, you still get the pass degree. If you do Honours and fail it, you still get the pass degree - though third class honours is so vanishingly rare that it is effectively a fail.
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    Mathematical Induction Inequality

    If you are still around, one approach with inequalities are to consider LHs > RHS in the form of LHS - RHS... So, in this case: \begin{align*} \text{Our induction hypothesis:} \qquad k^2 + 1 &> k \qquad \qquad \text{. . . . (*)} \\ \\ \text{We seek to prove:} \qquad (k + 1)^2 + 1 &> k + 1 \\...
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    Complex q

    If you are going to make edits, might I suggest the cases where you put (1 + \cos\alpha + i\sin\alpha)^k + (1 + \cos\theta - i\sin\theta)^k on pages 1 and 3 have the \theta's changed to \alpha?
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    MX2 Marathon

    The right angle is definitely OAC as the tangent to a circle is always perpendicular to the radius at the point of contact. If OCA was a right angle, then the tangent at A would be parallel to OC and thus OA would not be a tangent, but rather would cross the circle at some point B between O and...
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    trig proof

    Note that this should say that \pi\ \text{radians} \equiv 180^{\circ}. Also, it is important to get comfortable with working in radians as soon as you can. Calculus of trig functions does not work in degrees, and radians are not something added to irritate / confuse, they are essential for...
  6. L

    Complex q

    There are a couple of issues with question 1: On page 2, you have |z| = \sqrt{4\cos^2{\frac{\alpha}{2}}} = 2\cos{\frac{\alpha}{2}} but this is not always true: \begin{align*} \text{Take $\alpha = 2\pi$:} \qquad \cos{\frac{\alpha}{2}} &= \cos{\pi} = -1 \\ |z| &= \sqrt{4\times(-1)^2} = 2 \\ \\...
  7. L

    how to tell whether the product is aqueous or not in chemical equations

    I would refer to HCl (g) as hydrogen chloride or hydrogen chloride gas, whereas I would refer to HCl (aq), the acidic solution made by dissolving hydrogen chloride gas into water, as hydrochloric acid. Similarly, HCN (g) = hydrogen cyanide, HCN (aq) = hydrocyanic acid. For acidic substances...
  8. L

    how do I do this

    You can prove the answer is wrong by working from it... \begin{align*} \text{Put $f(1) = -6$ into} \qquad f(x) &= f(x+1) + x^2 \qquad \text{taking $x = 1$} \\ f(1) &= f(2) + 1^2 \\ -6 &= f(2) + 1 \\ f(2) &= -7 \\ \\ \text{Put $f(2) = -7$ into} \qquad f(x) &= f(x+1) + x^2 \qquad \text{taking $x...
  9. L

    Combinations

    \bullet \ \text{1 Ind, 5 Libs, 1 Lab:} \quad \binom{5}{1} \binom{10}{5} \binom{8}{1} \bullet \ \text{1 Ind, 4 Libs, 2 Lab:} \quad \binom{5}{1} \binom{10}{4} \binom{8}{2} \bullet \ \text{1 Ind, 3 Libs, 3 Lab:} \quad \binom{5}{1} \binom{10}{3} \binom{8}{3} \begin{align*} \text{Total...
  10. L

    help permutations and combinations question

    Suppose we had 10 balls of the five colours with no restrictions other than there must be at least 1 of each colour. Imagine the colours as different bins, into which we put some number of each colour - blue, green, pink, red yellow (BGPRY). A solution like B = 3, G = 1, P = 2, R = 3, Y = 1 is...
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    do you think australia would ever become a republic?

    It would depend a lot on the question, and on whether it had bipartisan support. Howard demonstrated how a determined opponent can do a lot of damage to a "yes" campaign, and Dutton would likely campaign against it. Also, if the model became the central issue, some voters wanting a republic...
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    Complex q

    Some immediate thoughts: What did you get for 2(a)? Have you noticed the two pairs of differences of two squares on the RHS? And that the resulting \cos^2{\alpha} terms can be found by rewriting into \cos{2\alpha} terms? \cos{4\theta}\ \text{is the real part of}\ z^4\ \text{when}\ z =...
  13. L

    help permutations and combinations question

    Carrying on from my earlier post, we had: Suppose we set the number or red balls, [text]r[/tex] to be at least 17, producing an invalid solution: \begin{align*} r + y + g + p + b &= 50 \\ (r'' + 16) + (y' + 3) + (g' + 3) + (p' + 3) + (b' + 3) &= 50 \qquad \text{where $r'' = r - 16$, so that}\...
  14. L

    Proof Perms

    As a general rule, unravelling the larger factorials makes for easier algebra: \begin{align*} \text{Required to Prove:} \qquad ^nP_r &=\ ^{n-2}P_r + 2r ^{n-2}P_{r-1} + r(r-1) ^{n-2}P_{r-2} \\ \\ \text{RHS} &= \frac{(n-2)!}{(n-r-2)!} + \frac{2r(n-2)!}{(n-r-1)!} + \frac{r(r-1)(n-2)!}{(n - r)!}...
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    Help with Permutations and Combinations

    Follow Up... how many permutations of the word PENCILS will have the "I", "C", and "E" occur in that order?
  16. L

    focal point

    Not any more, but it was until the start of 2020. A parabola (x - h)^2 = \pm4a(y - k) has its vertex at (h,\,k) and a focal length of a (which is the vertical distance from the vertex to the focus). So, for example, (x - 2)^2 = 4(y - 1) has its vertex at (2,\,1) and a focal length of a = 1...
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    Help with identifying transformations

    @ISAM77 's form is the general form: \begin{align*} y - h &= \frac{A}{x - k} \\ \\ y - 2 &= \frac{0.5}{x - 2} \end{align*} makes it easy to sketch... y - 2 = 0 \implies y = 2 is the horizontal asymptote (or, in the general case, y = h) x - 2 = 0 \implies x = 2 is the vertical asymptote (or...
  18. L

    help permutations and combinations question

    The problem is finding the number of different solutions of the equation r + y + g + p + b = 50 where r is the number of red balls, etc, subject to the constraints that: r,\,y,\,g,\,p,\ \text{and}\ b \in \mathbb{Z}^+ r,\,y,\,g,\,p,\ \text{and}\ b \ge 4 r,\,y,\,g,\,p,\ \text{and}\ b <...
  19. L

    should these guys be allowed to publically celebrate australia day?

    I wasn't aware of the other meetings, thanks for passing that info on.
  20. L

    Correct solutions?

    Not surprising as the solutions are poorly expressed and contain errors. Issues that I note include: It is not clear that the "coordinate for the tangent" refers to the point T where the tangent touches the curve and not the point P that we seek, where the tangent meets the axis. The...
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