Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Convergent or Divergent

  1. Oct 29, 2011 #1
    I need to find out if this function is convergent or divergent when finding the limit to infiniti.

    nsin(npi)

    How do I solve this? Do I use the squeeze theorem or lhospital rule?
     
  2. jcsd
  3. Oct 29, 2011 #2
    Evaluate the function in n=0,1,2,3,... Do you see a pattern??
     
  4. Oct 29, 2011 #3
    I want to know how to do this algebraically
     
  5. Oct 29, 2011 #4
    If you follow my hint then you can do it algebraically.
     
  6. Oct 29, 2011 #5
    It goes in increments of 180
     
  7. Oct 29, 2011 #6
    What is [itex]n*\sin(n*\pi)[/itex] for n=1,2,3,4 ???? What is the exact result??
     
  8. Mar 5, 2012 #7
    This sereis 1→∞ Ʃnsin (n∏) is equal to 1→∞ Ʃ(-1)^n (n) which is divergent hence given sereis is DIVERGENT
     
  9. Mar 5, 2012 #8

    HallsofIvy

    User Avatar
    Science Advisor

    What? Where did you get the sum from? The question was only about the sequence.

    realism877, do you not know what [itex]sin(\pi)[/itex], [itex]sin(2\pi)[/itex], [itex]sin(3\pi)[/itex], ... are? Your statement "it goes in increments of 180" implies that you do not, "[itex]\pi[/itex] radians" is the same as "180 degrees" but you should not have to convert to degrees to get this nor should you have to use a calculator. If you have taken a trigonometry or pre-calculus course you should know those "by heart"!
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook