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Thread: Any help with memorizing trigonometry identities?

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    Default Any help with memorizing trigonometry identities?

    Does anyone know of a good way to study trigonometry identities? like like (sin^2 + cos^2 = 1)... etc. ?

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    Quote Originally Posted by Sawyer View Post
    Does anyone know of a good way to study trigonometry identities? like like (sin^2 + cos^2 = 1)... etc. ?
    It is known that writing out something over and over is one of the best ways for memorizing something. Try practice problems or just writing out all the identities.
    I am Ggzz..

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    Practice problems, and realizing that they can almost all be derived from sin^2(theta)+cos^2(theta)=1.

    I always find that knowing where something comes from is extremely helpful (especially when it comes to math).

    E: If you are having homework problems you could watch videos from places like KhanAcademy and PatricJMT (I used these a lot for Calc because my professor was a moron).
    Last edited by Hazzah; 09-23-2013 at 03:07 AM.

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    I still remember how my math teacher in middle school taught us to memorize the following trigo identity using a pretty lame method -.-


    1. shopping + shoping = shopping center
    2. shopping - shopping = close shop
    3. cash + cash = credit card
    4. cash - cash = no (-) shopping spree

    (legend: s=sin, c=cos)

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    I tend to just work them out whenever I use them from first principles, far less to remember, only takes a fraction more in terms of time when you are using it, and way easier to code.

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    Thanks guys! I'll do a bunch of extra practice problems and look up some videos. I like algebra/calc, but idk if it's just the concepts or what, but trig is coming more difficult to me...

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    theyre all pythagorean identities

    sin is the y coordinate of a point on the unit circle
    cos is the x coordinate of a point on the unit circle

    a^2 + b^2 = c^2

    the radius of the unit circle is always one, so

    sin^2 + cos^2 = 1^2 (1)


    you can do that for these identities:


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    what really helped me was building the unit circle over and over and drawing the graphs. For the identities do what ever works for you, for me spacial awareness methods work.

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    Quote Originally Posted by Hazzah View Post
    Practice problems, and realizing that they can almost all be derived from sin^2(theta)+cos^2(theta)=1.

    I always find that knowing where something comes from is extremely helpful (especially when it comes to math).

    E: If you are having homework problems you could watch videos from places like KhanAcademy and PatricJMT (I used these a lot for Calc because my professor was a moron).
    Hello Hazzah,

    I wonder who was your professor and which university you studied at. Practically all courses at TAMUCC (where I used to work as a professor), for example, were based on KhanAcademy resources. The same with Trigonometric equations and identities - the course included not only the learning and practice modules, but also mnemonic methods as well for memorizing stuff. Not sure if there's a possibility to join it now, if you're not a TAMUCC student.

    Dr. Terry Lewis
    retired professor

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    Quote Originally Posted by DrPsyche View Post
    Hello Hazzah,

    I wonder who was your professor and which university you studied at. Practically all courses at TAMUCC (where I used to work as a professor), for example, were based on KhanAcademy resources. The same with Trigonometric equations and identities - the course included not only the learning and practice modules, but also mnemonic methods as well for memorizing stuff. Not sure if there's a possibility to join it now, if you're not a TAMUCC student.

    Dr. Terry Lewis
    retired professor
    TAMU as in Texas A&M??? or just a spam bot...

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    Quote Originally Posted by Ashaman88 View Post
    TAMU as in Texas A&M??? or just a spam bot...
    Seems legit, even has a profile picture with an old dude.

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