How to remember trigonometry ratios

By Murray Bourne, 05 Oct 2009

I recently tweeted the following (on Twitter, of course):

Tip for remembering sin, cos and tan: Some Old Hags Can’t Always Hide Their Old Age (sin = Opp/Hyp, cos = Adj/Hyp, tan = Opp/Adj)

There were several replies which I thought you may enjoy (some are a bit racey and not very politically correct – you’ve been warned):

From CardsChic: Oh Heck (sine) Another Hour (cos) Of Algebra (tan)

From sumidiot: From one of my students: Can A Hooker Take Off A Set Of Handcuffs?

From wmcneary: Some Old Hippy Caught Another Hippy Trippin’ On Acid

From tea_robot: “Saints On High Can Always Have Tea Or Alcohol” is what I was taught!

From LunaticNeko: My Tip: Open a “Book of Trigonometry Problems” or something, then drill through from beginning to end. You’ll remember it fast! ^ ^

From chris_1974: “Sex On Highways Causes Awful Havoc To Our Automobiles” is one a class once created!

See the 9 Comments below.

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9 Comments on “How to remember trigonometry ratios”

  1. alQpr » Blog Archive » How to remember trig ratios says:

    [...] cute mnemonics is fun, and the process of inventing and checking them may help reinforce the definitions, but [...]

  2. Qrystal says:

    And what about SOH CAH TOA? It’s short, it’s efficient, and it has precisely one meaning.

    I know, I know, this was all meant to be on the more amusing side, but useful can be clever too, can’t it?

    My personal favourite, the one I *actually use* when splitting something into orthogonal components (where one component calculation involves the cos of the angle and the other involves the sin), is simply “cos is close”.

    “Cos is close” basically means the same thing as remembering the “CA” part of “CAH” (cos, adjacent) but it has the added benefit of rhyming. By process of elimination, if cos is used for the component that is close to the angle, sin is the other one, the opposite. SOH!

  3. Aurangzeb Khan says:

    I would suggest,” Sleep On Highway Causes Awful Harm To our Attention”.

  4. satish persaud says:

    how can i put trig ratios into a poem/song!!!

  5. Murray says:

    Hi Satish

    Here’s one attempt:

    There are several other linked on that YouTube page.

  6. arvind pandit says:

    I’m gonna tell you how to memorise trignometric ratios faster and easier within a few minutes.
    1.first step is memorise this line i.e parhle beta parhle ha ha bapu.
    2. first sin = parhle/ha,i.e perpendicular/hypotenuse
    follow the step above to find out rest of the ratios of trigonometry.
    3.when cosec comes recipocal the lines ,then you will get the ratios.i.e ha/parhle – hypotenuse/perpendicular.

  7. Kashmirian says:

    In Kashmir, they call the adjacent side “base” and the opposite side “perpendicular” and hypotenuse is same.

    So the ratios are
    sin = perp/hyp
    cos = base/hyp
    tan = perp/base

    The rhyme they use is “Some People Have–Curly Black Hair– To Present Beauty”

  8. Old English says:

    I always remembered it with this:
    “The Old Archbishop, Sat On His, Coat And Hat!”
    (T=O/A, S=O/H, C=A/H)

  9. Manoj Nair says:

    The rhyme I learnt is somewhat:
    “Some people have, curly brown hair, turn permanently black”

    S=P/H
    C=B/H
    T=P/B

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