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  1. R

    Circle Geo. Help Pls

    I don't think Heron's rule is in the syllabus But nevertheless, it is still a quicker method of solving this question
  2. R

    What topic are you currently studying in 4 Unit?

    Complex numbers Graphing Polynomials Integration - Finishing
  3. R

    Integration by parts. Find S Sin(x)Cos(x)

    Finding the recurrence formulae for those gets ridiculous But integrating sin x.cos x ain't a problem
  4. R

    Online integration step by step website + more

    Re: Integration =] This is pretty interesting. Should come in handy when I find some tricky integrals =) Nice find!
  5. R

    hello do this simple poly question for me

    Question 2 (without using sum of roots) P(x) = 18x^3 + 3x^2 - 28x + 12 = 0 Since there is a double root, P(x) = P'(x) = 0 P'(x) = 54x^2 + 6x - 28 = 27x^2 + 3x - 14 = 0 (now use quadratic formula to find the zeroes of P'(x)) x = 2/3, -7/9 Therefore either 2/3 or -7/9 can be the double root...
  6. R

    Circle Geo. Help Pls

    24 cm There may be another easier method but this came up to my mind first
  7. R

    what topic is your school upto

    And you're only in Year 11 Oo? Well we just finished the 2U course; now we're doing Inverse Trigonometric Functions and later Further Applications of Calculus in the Physical World
  8. R

    Please Help! V. Hard Integration/Matrix Questions

    Mm yea I thought so, I've never heard of matrices before. Isn't this in the wrong forum then?
  9. R

    hello do this simple poly question for me

    LHS = x^3 + 3x + 2i RHS = (x - A)^2 . (x - B) = x^3 - (2A + B)x^2 + (A^2 + 2AB)x - A^2.B By equating the coefficients of x^2: 2A + B = 0 B = -2A Constant: -BA^2 = 2i -(-2A)A^2 = 2i A^3 = i A^3 = (-i^2)i [note: -i^2 = 1] A^3 = -i^3 A = -i Since B = -2A and A =...
  10. R

    Volumes by Cylindrical shells

    Here's the working out if anyone else needs it: dV = 2 pi xy dx = 2 pi x(4x^2 - x^4) dx = 2 pi (4x^3 - x^5) dx V = 2 pi INT([2, 0] 4x^3 - x^5) = 2 pi [4x^4 / 4 - x^6][2, 0] = 2 pi [32 - 64/3] = 32 pi / 3
  11. R

    Please Help! V. Hard Integration/Matrix Questions

    I want to help but I don't understand the notation of the conditions for the first question
  12. R

    Year 11 > Year 12

    In Year 11, you can bludge without feeling guilty In Year 12 however, you're gonna hate yourself if you screw up any assessments or go out too much. After all, Year 12 is the real thing and it's a competition across the state So the answer is no, Year 11 is not more stressful than Year 12
  13. R

    Pens: favourite type, colour etc

    Re: blue or black pen? I go for blue because it's the standard, isn't it? Well it looks neater than the black anyway
  14. R

    The Dumbest mistake u've ever made in a Maths Exam

    Shit, I can't take this anymore. Reading this thread is gonna change my concept of maths :|
  15. R

    Does SDD suck or what?

    Yea our Software Design class is boring Reading from the textbook makes me sleepy
  16. R

    Regret doing Standard?

    I was doing Advance last year but was dropped because the school wanted only the top 40 to do it. I was somewhere on the border line. I could've lodged an appeal to the Head Teacher about it but didn't bother. I half regret not doing Advance, knowing my English has significantly improved, but...
  17. R

    Volume question - Method of slices

    Ohh okay so I was on the right path all along Thanks
  18. R

    Volume question - Method of slices

    The arc of the curve y = cos x from x = 0 to x = pi / 2 is rotated about the y axis. Find the volume of the solid generated. Okay, so when the cos x is rotated about the y axis, it would form a solid similar to a bell. If I take a horizontal slice of it, the radius would be x units. Therefore...
  19. R

    Integration question

    Evaluate the integral of: sin x . cos x --------------- dx sin x + cos x One obvious method is using t-substitution but it doesn't seem to work out that easily. Are there any other working methods that can be used for this?
  20. R

    What's your prescribed text?

    Mine is the novel We All Fall Down by Robert Cornier
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