1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Sinusoidal Functions: describe transformations, sketch graph

  1. Aug 13, 2016 #1
    1. The problem statement, all variables and given/known data
    upload_2016-8-13_1-38-49.png

    2. Relevant equations
    none

    3. The attempt at a solution

    -amplitude is 3
    -period is 180°
    -right 60°
    -down 1

    Rough sketch of graph:

    upload_2016-8-13_1-42-40.png


    I would like to know if the graph looks right, is there any improvements to be made?

    Thanks :)
     
  2. jcsd
  3. Aug 13, 2016 #2

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    You got it wrong. That's the graph of ##y = -3\sin(2(x-60^o))-1##.
     
  4. Aug 13, 2016 #3
    wanna know why the line at 90?
     
  5. Aug 13, 2016 #4
    change the sign and it is alright
     
  6. Aug 15, 2016 #5
    I re-did the graph:

    upload_2016-8-15_2-24-35.png

    Is this better?
     
  7. Aug 15, 2016 #6

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    Still incorrect. Start from ##f(x) = 3\sin(2(x-60^o))## which can be obtained by translating ##f(x) = 3\sin(2x)## to [left/right, it's your part to answer] by ##60^o## degrees.
     
  8. Aug 15, 2016 #7

    Ok I have attempted the graph again:

    The dotted curve is the original base function y = sinx, and I used it to help apply the transformations. The dotted lines show where the axes have been shifted.



    upload_2016-8-15_20-0-46.png


    Is this an improvement??
     
  9. Aug 15, 2016 #8

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    Nope.
    Your first drawing is almost correct. It's just the negative sign in front of the sine function that needs to be removed. May be it's better to draw the functions resulting from each transformation. So, you start from ##y=\sin(2x)##, which is a harmonic function of period ##180^o## and amplitude 1. Then draw ##y=3\sin(2x)##. Followed by ##y=3\sin(2(x-60^o))## and finally ##y=3\sin(2(x-60^o))-1##. This is the only way we can spot in which step you went wrong.
     
  10. Aug 17, 2016 #9
    Okay, I have attempted the graph again, lets hope its an improvement at least :/

    upload_2016-8-17_22-12-35.png
     
  11. Aug 17, 2016 #10

    blue_leaf77

    User Avatar
    Science Advisor
    Homework Helper

    Yes, that's the correct one.
     
  12. Aug 17, 2016 #11
    Thanks for the help! I really appreciate it :biggrin:
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Sinusoidal Functions: describe transformations, sketch graph
Loading...