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Homework Help: How Can I Graph THis trigonometric Function?

  1. Jul 9, 2006 #1
    Cud u Help Me How to Graph these?
    y = 2 + sinx ; where x = teta
    y = 2sinx ; where x = teta

    cud u give me some ideas pls?
  2. jcsd
  3. Jul 9, 2006 #2
    Do you know how to graph the function y = sinx ?

    If you do then what does adding 2 to the y value of that function do to its graph. Similarly for multiplication.
  4. Jul 9, 2006 #3
    it would look like this one
    http://jwilson.coe.uga.edu/EMT668/EMAT6680.2001/Mealor/writeup1/assignment 1.html
    but i still dont understand why...
    My problem is that what would it look like when i add 2 and multiply 2?

    oh yeah when u add 2, the y - axis would move from 0 to 2...
    the only problem i have is that how come that is the sine wave?
    how to prove it?

    Edit number two:
    I see... so thats what it is.... http://www.ies.co.jp/math/java/samples/graphSinX.html [Broken]
    so meaning when the waves move its gonna show a rotation of a circle
    ..,.... so how would it look like when i multiply it by 2 or add by 2?
    Last edited by a moderator: May 2, 2017
  5. Jul 10, 2006 #4
    Look in the first link you posted. It tells you what happens when you multiply by 2.

    BTW, when you add 2, it's not the y-axis that moves. The y-axis does not move. Ever.
  6. Jul 10, 2006 #5


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    Science Advisor

    First of all, why is this in the Engineering homework section?

    Secondly, did you read the link you posted? You ask what the plot looks like when you multiply the sin function by 2 and when you add 2 to the sin function.

    Do you know what the basic format of the sin fuction is? it is:
    [tex]f(\theta) = Asin(\theta)[/tex]

    "A" is the amplitude of the function and is a MULTIPLIER. So what happens to the amplitude of the sin wave when you change the value of A?

    To give you a hint as to the addition problem, think of the sin function like this: When you graph the plain sin function, the waveform starts and ends at the horizontal axis, right? In that case the function could be written as [tex]f(\theta) = 0 + Asin(\theta)[/tex]

    Now, what do you think that changing the 0 to a 2 does?
  7. Dec 15, 2009 #6
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