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Homework Help: 10 Calculus Questions Integrals,Equations, PDF file, Dead line after 1 hour

  1. Sep 19, 2012 #1
    Uploaded a pdf file

    My Answers :

    a- x= 1/10 (9-√41) ≈0.259688,Or x=1/10 (9+√41)≈1.54031
    b:y=0 Or y=7/3
    c: didn't solve.
    d: t= 1/3 log⁡(5/2)≈0.30543
    e::β=3/5 Or β=-3/5

    2: didn't solve.

    tan (0.59)≈0.67

    4: didn't solve

    We solve the equation
    α= 2tan^-1⁡(1/7 (3-√2))〗
    We calculate sin⁡(2α)

    6:max⁡{f(x)=x^3-5x^2-8x+12}=400/27 at x=-2/3

    a: 0
    didn't solve b,c,d,e

    8: The angle is 109.5 degrees

    a :: e^2x (6x^2+6x-sin⁡(x)+2 cos⁡(x)+10)
    b: 6y log⁡(5)
    c: sec⁡θ
    d: 800
    e: z( log⁡(z)-1)+constant

    10 : didn't solve.

    Attached Files:

  2. jcsd
  3. Sep 19, 2012 #2
    Please also show your work instead of just the answers, thank you.
  4. Sep 19, 2012 #3
    If i want to type the work i did it would take about 2 hours i'm sorry i'm slow at typing and now time is against me , i started since 3 hours.
  5. Sep 19, 2012 #4
    If you don't type out the work you did, then I'm afraid nobody here is going to help you.
  6. Sep 19, 2012 #5


    Staff: Mentor

    why not take a picture of your handwritten work or scan it and post that just like you did with the pdf?
  7. Sep 19, 2012 #6
    Guys please help me right now and after sending my answers to my teacher i'll tell you my work on each of the problems

    i don't have a scanner the pdf was sent by the teacher

    and the teacher said you can seek help with other people

    because the questions are hard
  8. Sep 19, 2012 #7
    Nope, that isn't possible. PF isn't a place where you go, ask a question and immediately get an answer.
  9. Sep 19, 2012 #8
    Well, you will get immediately an answer if you show some work :wink:

    Seriously though, you received this assignment a week ago and you're asking for help an hour before the deadline?? That's poor planning from your side. Next time, you should ask for help earlier.
  10. Sep 19, 2012 #9


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    Since you are pressed for time, I will save you a little time by quoting from the FAQ thread, which is first top thread in this group.


    "Did you post that your homework is due in a few hours and that you need help NOW?
    If you did, then you should remove this. It doesn't get you a faster response. Some people even refuse to help posters who post things like "ASAP", "Help needed fast", etc.
    Also, if your homework is due in a few hours, then perhaps you should have asked help on it earlier. People here are volunteers and are not paid to help you. We will answer when we can, but it's not nice to put us under pressure."
  11. Sep 19, 2012 #10
    the date was when the pdf was created not received by me, i received this pdf today before 4 hours

    if i knew how to solve them i wouldn't have asked :(

    time is running out i'm not asking for an immediate answer i'm asking where to start

    PS: our teacher gave his this homework without teaching us about functions and derivatives
    i wrote these answers after reading a simple paper about functions and derivatives

    i tried solving them before posting on the fourms

    YES : I just talked to the teacher the deadline was change to next Wednesday instead of today :)
    Last edited: Sep 19, 2012
  12. Sep 19, 2012 #11
    Deadline was changed now i have a whole week to solve the problems :)
  13. Sep 19, 2012 #12
    Good, then which question would you like to start with? It would have been better if you made a seperate thread for each question.
  14. Sep 19, 2012 #13


    Staff: Mentor

    Yes, I agree. You (Phys student) will likely get more helpful responses by showing a single problem with your work than by throwing up a whole laundry list of problems.
  15. Sep 19, 2012 #14
    Let's start with problem 7

    (e) if m1=m2=m3

    i'll convert everything to m1

    a= g(3m1m1-4m1m1-m1m1)/(m1m1+m1(4m1+m1)

    simplifying (3m1^2 -4m1^2-m1^2)/(m1^2+4m1^2+m1^2)
    (-2m1^2)/(6m1^2 )
    -2/6 = -1/3
    a= g*(-1/3)

    and what is meant by m1 is much larger than m2 and m3 ?
  16. Sep 19, 2012 #15
    That looks right.

    m1 is much larger than m2 means you can neglect m2 when you are performing operations such as addition or subtraction with m1 and m2.
  17. Sep 19, 2012 #16
    if the title got changed it would be better to avoid confusion
  18. Sep 19, 2012 #17


    Staff: Mentor

    m1 >> m2 means that whenever you're adding m1 and m2 you can simply use m1 as if m2 is effectively zero.
  19. Sep 19, 2012 #18


    a= g*-1

    a= -g
  20. Sep 19, 2012 #19
    That's again correct.
  21. Sep 19, 2012 #20
    and when m1 is smaller than m2 and m3 is that the opposite ? we neglect m1 when doing addition and subtraction with m2 and m3 ?
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