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    2u Mathematics Marathon v1.0

    Answer to Q1: Question 2 If y = 2x2ln(5x) then find d2y/dx2.
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    Math question, please help :)

    I can assure you, however, that no first principals will be examined in 2 unit yet alone 3 unit... first principals is extension 1 prelim work and so it can be (and has been) tested in hsc 2u never learn it, they just use the formulas
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    probability (simple)

    yeah they're using 3u method but it's basically the same thing using 2u is much simpler to look at P(at least one japanese) = 1 - P(no japanese) = 1 - (7/10 * 6/9 * 5/8 * 4/7) = 0.8333...
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    omg...why can't i do this....?

    alright my bad
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    need help with projectile motion

    I assumed it -10m/s^2 If you assume g = 9.8 then in theory throwing the projectile up will never fall down and since the ball is always accelerating up at a faster rate than the second you shouldn't even get an answer... Velocity is a vector quantity and since gravity pulls objects down...
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    Counting/ Permuations

    You're not trying to find the probability so you don't need to divide the answer by the total amount of possible combinations Taking 3 letters at random from 8 letters = 8P3 ...divide by 2! because of the recurring E 8C3/2! = 168 possible letter sequences
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    need help with projectile motion

    it's being fired vertically up so there are no angles involved projectile 1: consider vertical motion a = -10 v = -10t + c at t = 0, v = 49, so c = 49 v = -10t + 49 y = -5t^2 + 49t projectile 2: consider vertical motion a = -10 v = -10t + c at t = 2, v = 49 49 = -20 + c c =...
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    stupid permutations

    So these 4 (successive) events can happen in 5C1 x 8C1 x 10C3 x 14C2 different ways This is impossible.. choosing 7 from 23 is 23C7 without restrictions, so it cannot be higher than this. You have to take each possibility one at a time: 1 independent, 1 labor, 5 liberal 1 independent...
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    (x+1)^3-y^3

    You are confusing this with the difference of two cubes. (a + b)³ = (a + b)(a² + 2ab + b²) = a³ + 3ba² + 3ab² + b³ to solve that try this: let m = x + 1 m³ - y³ = (m - y)(m² + my + y²) and substitute
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    Algerbra- practice questions

    you might want to retry that :)
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    Maths Competition

    http://www.artofproblemsolving.com/Forum/forums.html /kids from this forum beg to differ
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    help needed

    if it's a tangent to the x and y axes, then the center of radius lies on the line y = x so let the center of the circle be (xc,xc) xc is the radius perpendicular distance between center and tangent (which is the radius) xc = |4xc + 3xc - 60| / 5 (equal radii) 5xc = |7xc - 60| 5xc = 7xc...
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    Trig - General Solutions (help needed)

    something like.. sin3x = -sinx sin3x = sin(-x) if sinθ = sinα then θ = nπ + (-1)nα 3x = nπ + (-1)n(-x) 3x - (-1)n(-x) = nπ 3x + (-1)nx = nπ x(3 + (-1)n) = nπ x = nπ/(3 + (-1)n) don't know if you can do that i just made it up
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    My probability question #1

    P(selects 2 caramel chocolates): 3/10 * 2/9 * 7/8 * 3C2 = 7/40 P(selects 3 caramel chocolates): 3/10 * 2/9 * 1/8 = 1/120 Therefore, P(selects at least 2 caramel) = 7/40 + 1/120 = 11/60 or ... P(selects no caramel chocolates): 7/10 * 6/9 * 5/8 = 7/24 P(selects 1 caramel chocolate)...
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    Probability

    on a more serious note, yea they're both correct
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    True or False?

    false. 1 is a positive integer.
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    Natural growth & decay question

    the initial population was 500. it then 'falls' to the limiting population of 100. for it to fall within 10 of the limiting population, the population would be 110. if the population were intially 2 and the limiting population were 100 then it would ask for the time taken for the...
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    need help with an algebraic question!!

    really? do show your working..
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    need help with an algebraic question!!

    i found the question quite tough... but managed to get it finally. dont know if its very efficient tho. let: A = 2a-b B = 2b-c C = 2c-a then A+B+C = a+b+c = 0 to prove: A^3 + B^3 + C^3 = 3ABC since A+B+C = 0 thus cubing both sides, (A+B+C)^3 = 0 expand and voila! expanding...
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    ATM information system participants

    the only participants in an ATM information system (banking transactions, transfers between accounts) would be the people in the environment? people using the ATM? could someone clarify me on this? thanks..
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