How do you determine the phase shifts for sine and cosine graphs

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  • Опубликовано: 15 окт 2024
  • 👉 Learn the basics to graphing sine and cosine functions. The sine graph is a sinusiodal graph with x-intercepts at x = 2n*pi, maximun value of 1 at x = pi/2 + 2n*pi and minimum value of -1 at x = -pi/2 + 2n*pi. The cosine graph is a sinusiodal graph with x-intercepts at x = n*pi/2, maximum value of 1 at x = 2n*pi and minimum value of -1 at x = (2n - 1)pi. To graph the sine and the cosine graph, we plot the above points on the x-y coordinate plane and graph accordingly.
    After we have graphed the parent graph, we then apply the required transformations to the sine/cosine graph. The amplitude is the maximum point on the graph, the period is the distance/time for a complete oscillation, the phase shift is the horizontal shift from the parent function, the vertical shift is the vertical shift from the parent function.
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Комментарии • 149

  • @isaacliu._.6899
    @isaacliu._.6899 4 года назад +66

    This dude deserves every single one of his subs and more. When khan academy is not really helpful, I look to here and to OCT and I honestly think you both deserve more subs as well as a pay raise.

  • @AG-jp2ni
    @AG-jp2ni 9 лет назад +38

    Finally! An explanation as to why the phase shift of the cosine graph is so damn tricky! Thanks a million.

    • @brianmclogan
      @brianmclogan  9 лет назад +3

      Lenny Shelby you are very welcome!

  • @TylerSimsMechanical
    @TylerSimsMechanical 4 года назад +7

    Whenever I search up a math question and I see a Brian Mclogan video, it's always a no-brainer to watch because it's always time well spent! Thanks, Brian!

  • @andrewpark78
    @andrewpark78 8 лет назад +8

    This video probably saved at least 40-60% of a test. Much love

    • @brianmclogan
      @brianmclogan  8 лет назад +1

      you are very welcome! best of luck!

  • @uzielsaldivar8038
    @uzielsaldivar8038 2 года назад

    Dude man, I spent an hour trying to understand "mylabs" technique and still couldn't get it, and here you are teaching me the concept in 7 minutes. You are such an amazing teacher

  • @cphillips8296
    @cphillips8296 6 лет назад

    I think this is the best video about this on RUclips. Literally a life saver

  • @myprogress6498
    @myprogress6498 7 лет назад +49

    better than khanacademy

  • @thereisnoiintheteam8475
    @thereisnoiintheteam8475 8 лет назад +6

    Thanks. This the only video that made it clear for about the phase shifts!

    • @brianmclogan
      @brianmclogan  8 лет назад +1

      +Majd Semaan awesome! they get a lot of people, happy to clear the confusion for you

  • @bogella2225
    @bogella2225 7 лет назад +2

    Thank you for making these videos. Helped me understanding my online Trig class much better.

    • @brianmclogan
      @brianmclogan  7 лет назад

      you are very welcome! happy to be able to help you out!

  • @SylvanSerenity
    @SylvanSerenity Год назад

    Aha! Setting the transformation equal to zero makes so much more sense to me now. Thank you sir!

  • @CALISUPERSPORT
    @CALISUPERSPORT 4 года назад +4

    I'm teaching my Pre-Calc classmates your "initial period" trick as the "McLogan Method" lol. Before that, everyone was wracking their brains so much on calculating the x-axis values when there's a phase shift.

  • @Averyforehand
    @Averyforehand 2 года назад

    Just wanna say. Thank you for your help. I’ve never been the greatest at math but your videos truly help!!!!!!!!

  • @TonyandDylan
    @TonyandDylan 5 лет назад

    This video needs over a million views.

  • @verenicepatino9793
    @verenicepatino9793 6 лет назад +2

    Couldn't even learn this in class and I learned it on RUclips! Thank you!

  • @wistfulgraph
    @wistfulgraph 3 года назад

    For me I learned that you can factor what’s in the function in order to get the phase shift. It was always confusing why you would do it and also trickier in some instances. Now it makes a lot more sense with it equaling to zero. Great vid.

  • @BeTheFUTURE
    @BeTheFUTURE 2 года назад +1

    Thank you so much. I really appreciate your dedication and passion for teaching. Wouldn't have been able to finish my math HW without this video haha

  • @feli5715
    @feli5715 Год назад +2

    Always with the great videos👏

  • @andrewdemos3009
    @andrewdemos3009 2 месяца назад

    in precalculus right now stuck on this correlation yoo🔥🔥

  • @dudedude9528
    @dudedude9528 4 года назад

    Thanks the period kept making me get them wrong because i did not realize it impacted my phase shift also my professor gets them by doing a 3 inequality interval like 0 is less than and greater to pie(x-pie) is less than greater to 2pie but it is a longer process and throws me of but thank you a million

  • @itsFarawaySkies
    @itsFarawaySkies 10 лет назад

    I had a problem on my homework that read " y = 6 cos (3 x - 2) " , it was marking me wrong for answering -2 or 2 for phase shift and looking for the answer "2/3" as the face shift. After doing what you mentioned to do, in my case set 3x-2=0 I would get the answer x=2/3 or in other words c/b. I was confused with with the formula c/b because I would want to carry over the negative sign from (-2) and use -2/3. However, setting 3x-2=0 makes me realize why the answer is 2/3. Thanks for sharing the initial period information, it does help!

    • @brianmclogan
      @brianmclogan  10 лет назад

      yeah! awesome! happy it worked for you

  • @amysantos2876
    @amysantos2876 6 лет назад +1

    Thank you so much for doing these videos! If every math teacher I ever had gave a shit like you, Math would not be a struggle for me. You engage, make is simple to understand and explain these problems thoroughly. You have seriously helped me in College Trig. THANK YOU!!!!!
    Sometimes your videos are better then Khan academy and thegreatcoursesplus,

    • @brianmclogan
      @brianmclogan  6 лет назад

      cheers Amy! so happy to be there for you!!

  • @ericraywood8108
    @ericraywood8108 9 лет назад +83

    that sigh at the end xd

  • @harrymcdonald3456
    @harrymcdonald3456 10 лет назад +3

    You're a good teacher :) keep it up

    • @brianmclogan
      @brianmclogan  10 лет назад +2

      Harry McDonald thank you will do

  • @wexer82
    @wexer82 7 лет назад +5

    Man, I should have watched this last night, I got this one wrong on my exam. Great video, I'm a pro at phase shifting now.

    • @brianmclogan
      @brianmclogan  7 лет назад +1

      haha, as you should be, now you know

  • @vwsandvettes3253
    @vwsandvettes3253 3 года назад

    I like your style and presentation Brian. You have that "math guy" look. :-) I was a high school math flunkie lol, and it took me military service and college before it all "clicked", and I'm still no guru. I remember all the people that "got it" (math that is) around me in high school and I also remember being lazy and immature. I wish I'd had more motivation but better late than never!

  • @ethancooper4154
    @ethancooper4154 9 лет назад +3

    But what is the phase shift's role in a circle? Like if you are given a problem for a certain real-life circle and you need to write its sine or cosine function it's simple to find the amplitude and period etc. but since it's not actually on a graph, as it is a real object, how do you know its not phase displacement?

  • @DavidMartin-tg2lz
    @DavidMartin-tg2lz 8 лет назад +1

    totally helped right before my test tomorrow!!!!

    • @brianmclogan
      @brianmclogan  8 лет назад

      +David Martin happy to help, good luck

  • @maxpowergaming3496
    @maxpowergaming3496 8 лет назад +28

    randy ortan ... Thanks

  • @tonyahanagriff4637
    @tonyahanagriff4637 3 года назад +2

    dang, your better then my trig teacher. imma senior in highschool trying to pass trig.

  • @kelvinrodriguezjr2184
    @kelvinrodriguezjr2184 4 года назад

    I didnt pay attention in highschool math and am now paying the price in college thank you for these videos they help me alot

  • @DreamDawn21368
    @DreamDawn21368 5 лет назад

    your videos are literally saving my life rn

  • @incues
    @incues 5 лет назад

    Awesome dude, great breakdown of the calculations, I finally understood it

  • @AngeloTaracena
    @AngeloTaracena 9 лет назад +2

    Need help finding out wavelength, phase shift and phase angle of an AC voltage is expressed as 240 cos(2765t - 45°).
    is the phase angle -45 degrees
    and is the phase shift +45 degrees?
    please help thank you

    • @brianmclogan
      @brianmclogan  9 лет назад +2

      Angelo Taracena not set 2765t-45 = 0 then solve for t, that will be your phase shift. If there was not a coefficient of 2765 then your answer would be correct. When it is there, it effects the phase shift so the best way to determine the effect is to set equal to zero and solve.

  • @slimeball4l540
    @slimeball4l540 4 года назад

    does the frequency affect the phase shift? for example this question for my math is y = -5 + 3cos 3(theta + pi/4) would the phase shift be pi/4 or 3pi/4? thanks

  • @AntXUnofficial
    @AntXUnofficial 7 лет назад +53

    It takes a piss @ 4:50

  • @dumbt
    @dumbt 4 года назад +5

    these random math channels are way better than the actual teachers lmao. Then again my math teacher is good it's just that he doesn't make it fun so we don't pay attention

  • @pranavraja9045
    @pranavraja9045 3 года назад

    I just factor the pi out so cos(pi(x+1)) meaning the graph moves 1 unit to the left and since the or the inflection point is x=-1

  • @fy-g01abayaperla.99
    @fy-g01abayaperla.99 3 года назад

    hi sir! I just have a question. What is the unit for phase shift? Is it only by radians or it can be by real numbers?

  • @mounandi9163
    @mounandi9163 3 года назад

    would it be possible to simply factor the pi inside the parentheses and see that it's pi(x+1) and shift the equation 1 to the left

  • @rickyvij3137
    @rickyvij3137 8 лет назад +34

    I am gonna fire my teacher and Hire you.

    • @brianmclogan
      @brianmclogan  8 лет назад +5

      +ricky vij haha, here all day long for you, happy to help

  • @BoZhaoengineering
    @BoZhaoengineering 5 лет назад

    you may graph any function by yourself with phase shift and intercept. And compare how the plot of the functions work on graph. Definitely the same result. you do not even a mapping such as sine function. you only need a set X and the range of the set f(X). It is tricky and it is fun.

  • @earlybirdhitstree
    @earlybirdhitstree 9 лет назад

    How would you graph f(x)=cos x-3? Is the period 2pi with a phase shift of 3 to the right? How would I find the units on my graph so I could plot some points?
    I'm so lost...

    • @brianmclogan
      @brianmclogan  9 лет назад

      earlybirdhitstree yes you are correct with the phase shift and period. I would take the parent graph cos(x) and move the max/min and intercepts three units to the right. For instance a maximum point on cos(x) occurs at when x=o and 2pi. The max points would not occur at 3 and 2pi+3. You may want to use your calculator and covert the numbers to decimal form to aide in graphing

    • @earlybirdhitstree
      @earlybirdhitstree 9 лет назад

      Mr. McLogan's Math Channel Oh okay!! Thank you so much!!! :-)

  • @YKULTRA
    @YKULTRA 6 лет назад

    this was a great vid! so thankful!

  • @thomasnguyen4943
    @thomasnguyen4943 8 лет назад

    Good explanation, thank you !

    • @brianmclogan
      @brianmclogan  8 лет назад

      you are very welcome! happy to be able to help!

  • @Supermario0727
    @Supermario0727 8 лет назад

    So if you set "bx - c" equal to 0, then solve for x, that will tell you the phase shift? If so, how do you know whether the graph is shifted to the left or right based on the x value.

    • @brianmclogan
      @brianmclogan  8 лет назад

      +John Stuart yes, x-(h) where the value of h is your horizontal transformation h positive right, h negative (h-(-h)) or (x+h) left

  • @juanbriceno7385
    @juanbriceno7385 6 лет назад

    Very helpful video but i tried the same START/END method and what was supposedly my END POINT, actually wasn't after i added the T/4 to my starting point and to my 2nd/3rd point.

  • @Sultan_A
    @Sultan_A 6 месяцев назад +1

    Very Gd, KIUp

  • @alexandram7257
    @alexandram7257 9 лет назад +1

    came here to double check my understanding but solving for x through bx-c=0 seems like a lot more work than just taking b out in front of the bracket

  • @Epitome2
    @Epitome2 7 лет назад

    Thank Mr proffessor.

  • @Omarkhaled19997
    @Omarkhaled19997 3 года назад

    Very good.

  • @anirudhb9916
    @anirudhb9916 7 лет назад

    Thank you so much... This helps alot

  • @stephenstruble5064
    @stephenstruble5064 5 лет назад

    So I'm pretty sure I understand how phase shift works. Or atleast I thought I did. Here is the problem.
    y = -3sin(6x+π/2)
    |Amplitude| = 3
    Period = π/3
    Phase Shift = -π/12
    All of that is correct so far, but when I graphed the function it said -π/12 for the phase shift was wrong and it would only accept the answer when I made it positive. How can I be right for the phase shift, but wrong when graphing the function?

  • @free-energy-systems
    @free-energy-systems 4 года назад +1

    You know son, I remember when I was young like you. We played pong and not beer pong. Nintendo had this really cool game that was invented 10 years earlier. Yep, scientists had fun playing pong in the 1960's. As it turns out, that was way cooler than going to the Moon. As far as the Moon goes, Galileo realized that the Earth orbited the Sun because Venus had phase shifts like the Moon. ergo, phase shifts are cool. And I understand that this might be before your time. :) p.s., am having some fun and letting kids know that phase shifts actually have a place in the history of science.

  • @marketinginsightsgroup6345
    @marketinginsightsgroup6345 6 лет назад

    that s really helpful thanks

  • @sayrahqaiser1921
    @sayrahqaiser1921 9 лет назад

    so for y= -1/4cos1/3(x-50 degrees)-9 would the phase shift be +50 degrees since there is nothing in front of the x. And all together would the transformations be vertical compression by a factor of 1/4 of the original height y=cosx, phase shift = 50 degrees, horizontal stretch by a factor of 1/3, vertical translation 9 units down and reflection on the x-axis???? PLEASE HELP thank you

    • @brianmclogan
      @brianmclogan  9 лет назад

      Sayrah Qaiser The (1/3) should be in front of the x changing the phase shift to 150 degrees. I have never seen a problem how you have it written so I would assume the 1/3 is in front of the x. If so everything else you have described is correct

    • @sayrahqaiser1921
      @sayrahqaiser1921 9 лет назад

      Mr. McLogan's Math Channel THANK YOU so much, and does amplitude = radius

  • @aftc-bz2oi
    @aftc-bz2oi 7 лет назад

    If i only have the graph, say the equation hasnt been given, but its y=sin(9.7x+4.8) - 14.8
    Is there a way to find phase shift? I tried graphing heavy decimal graphs, but i find it hard to get phase shift,unless i cheat with the equation. I want to be able to do it raw, just straight numbers.

    • @brianmclogan
      @brianmclogan  7 лет назад

      you know the parent graph of sine crosses at the origin, so you can measure how far the next intercept is for the graph and determine that to be the phase shift. You can do the same with cosine but use (0,1) as the initial point of the parent graph as the max

  • @GrandNecro
    @GrandNecro 9 лет назад

    wish you can be my teacher, so much better at explaining than mine

    • @brianmclogan
      @brianmclogan  9 лет назад

      GrandNecro thank you happy to be able to help you out!

  • @shimabegum2552
    @shimabegum2552 6 лет назад

    Can you explain how am I supposed to know by looking at the graph if it is Sin or cosine ?

    • @brianmclogan
      @brianmclogan  6 лет назад +2

      without any transformations sine crosses the origin and cosine does not, that is one easy distinction

  • @sophatotid1170
    @sophatotid1170 7 лет назад

    Thank you very much

  • @mariacastillo-dw1yd
    @mariacastillo-dw1yd 8 лет назад

    So if im given a graph, the phase shift would be the period?

    • @brianmclogan
      @brianmclogan  8 лет назад

      +Maria fernanda Castillo no the period is the length it takes for the graph to repeat itself, phase shift is the horizontal transformation

  • @OVERWATCHfly
    @OVERWATCHfly 8 лет назад

    How do we determine the (bx-c) when we are only given a graph? I understand that you can use the period to find B, but I still don't get how you can set (bx-c) = 0 when you don't have c.

    • @brianmclogan
      @brianmclogan  8 лет назад

      +Savas_7 c is the horizontal transformations, so if there is none then it would be bx=0

  • @samgladnick8436
    @samgladnick8436 8 лет назад

    I am solving a sinusoid at the moment and am wondering what the letter "b" stands for in the equation?

    • @brianmclogan
      @brianmclogan  8 лет назад

      +Alakasam RUclips it affects the period of the sinusoid, try graphing with different b's to see the effect

    • @diygarygaming
      @diygarygaming 7 лет назад

      It doesn't stand for anything. It's just a letter...The equation is y=asin(bx-c) + d
      if you notice, they're just selecting letters from a->z to use as a variable.

  • @jojotsi8
    @jojotsi8 5 лет назад

    How does phase shift affect the period of a graph

  • @muhammadseyab9032
    @muhammadseyab9032 6 лет назад

    good explanation

  • @ShubhamKumar-rp5nl
    @ShubhamKumar-rp5nl 7 лет назад

    sir can u make lecture for general competition exam...

    • @brianmclogan
      @brianmclogan  7 лет назад

      I do not know what is on a general competition exam but either way I am sorry I only have time to work on my current classes I am teaching

  • @vertigo0331
    @vertigo0331 3 года назад

    If you're like me and don't need the review, he gets to the phase shift at 6:40 or so

  • @JosemariaCarrascoMolina
    @JosemariaCarrascoMolina 4 месяца назад

    I felt that sigh at the end lol

  • @hillaryjacobs8627
    @hillaryjacobs8627 7 лет назад +1

    the sigh at the end is great. lol

  • @davidrabar3977
    @davidrabar3977 4 года назад

    Okay but how do you define C and B if we dont know them in a task

  • @0claver
    @0claver 9 лет назад +2

    THANK YOUUUUUU

  • @ratatouille3536
    @ratatouille3536 4 года назад +1

    1:27 he meant 1 unit to the left

  • @darthvader4899
    @darthvader4899 6 лет назад

    thanks a lot keep goin

  • @mariss4446
    @mariss4446 2 года назад +1

    Wrong wrong wrong.
    The correct way to write the sine function is
    y=AsinB(x-C)+D
    The way you wrote it is
    y=Asin(Bx+C)+D which is wrong. You distributed B across x, but not across C. Rookie mistake.
    You shouldn't distribute anything.
    If the phase shift is +/- pi then you write it as +/- pi, no matter the value of B.

    • @brianmclogan
      @brianmclogan  2 года назад +1

      Yes, I prefer that form as well. You can still determine the correct phase short by factoring out b which I believe I was trying to achieve as most equations do not have b already factored out

  • @luisjoya7920
    @luisjoya7920 8 лет назад

    mr mclogan. youre mcbest

  • @mackenziekoehn5594
    @mackenziekoehn5594 3 года назад

    i wish he was my math teacher.

  • @녹성-n5p
    @녹성-n5p 4 года назад

    RESPECT

  • @AestheticMat
    @AestheticMat 8 лет назад

    @Free Math Videos hahaha that exhale at the end tho, jokes aside thank you for the clarification

  • @kidooaddisu2084
    @kidooaddisu2084 6 лет назад

    Thanks

  • @_Nahian
    @_Nahian 8 лет назад

    I still don't understand how you would do this in a Real Life Situation. So lets say a ferris wheel problem came up, and you are asked to find the values of a, b, c, and d... how would we find the value of c?
    This is if we are not given a graph.

    • @brianmclogan
      @brianmclogan  8 лет назад

      +Nahian Fariha then you will want to create a graph to represent the situation

  • @alindasalas5464
    @alindasalas5464 3 года назад

    here in 2020 trying to learn math because online learning is vv difficult :O

  • @thatomofolo452
    @thatomofolo452 Год назад

    🙋👍👍

  • @myleefolau
    @myleefolau 4 года назад

    Usually everything I hear you say makes sense but this one I am completellyyyyyy lost

  • @gabiardila4078
    @gabiardila4078 5 лет назад

    PERIODTTTT

  • @shimabegum2552
    @shimabegum2552 6 лет назад

    Aren't it supposed to shift to left on 1:26 min?

  • @baileyayyy5085
    @baileyayyy5085 6 лет назад

    i love u

  • @Theoretically00
    @Theoretically00 6 лет назад

    Yasss

  • @raramasser8511
    @raramasser8511 4 года назад

    4:06 he speaks Spanish

  • @awesomevid5447
    @awesomevid5447 5 лет назад +1

    Randy ortan. 😂

  • @TheBigBangggggg
    @TheBigBangggggg 7 лет назад +6

    Do more graphing and less talking!!!

  • @peakplzzz626
    @peakplzzz626 6 лет назад

    I can’t watch this guy he talks to much

    • @brianmclogan
      @brianmclogan  6 лет назад

      Would you prefer I just do the work and not talk, or are you specifically talking about this video I talk and don't do the work because I have a lot of videos

  • @manahilsabeeh7148
    @manahilsabeeh7148 7 лет назад

    2pie/pie is pie not 2

  • @rooblejama2701
    @rooblejama2701 5 лет назад

    To be honest this guy didn’t explain anything