Helpful trick for Trig!

[LightAtTheEnd]

Hey guys,

I wanted to share this helpful trick to rememember some of the trig on the unit circle. I think it's the only thing I ever retained from my geometry class haha! It's takes some effort to grasp, but once you do, it's so easy to whiz by many of the trig questions, and heaven knows we already have too much too memorize.

1) Put your hand out in front of you palm facing up, I generally use my left hand. Each finger corresponds to an angle:
Pinky - 0
Ring - 30
Middle - 45
Index - 60
Thumb - 90

2) To figure out the number value for sin, cos, or tangent for an angle, fold down the finger for that angle.
So if I wanted to find a sin, cos, or tan value for 30 degrees, I fold my ring finger.

3) SIN: The sin value will be: sqrt(fingers below the folded finger)/2. In this case, if I fold down my ring finger, I have one finger "unfolded" below it, so sqrt(1)/2 = 1/2 = sin30

4) COS: The cos value will be: sqrt(fingers above the folded finger)/2. If I fold my 30 degree finger, I have 3 fingers above my folded finger, so sqrt(3)/2 = cos30

5) TAN: For tan, flip your whole hand over so palm is facing away from you with the ring finger still folded. The tan of 30 degrees will be: sqrt(fingers on top of folded finger)/sqrt(fingers below the folded finger). In this case, sqrt(1)/sqrt(3) = 1/sqrt(3) = tan30.

I know it looks complicated but I promise if you put 10 minutes of effort into memorizing it, it will be so much easier to recall simple values not only for the DAT but for the rest of your life. (Not that you need to, but hey it's a neat http://www.vbulletin.org/forum/misc.php?do=bbcode#sparty trick.)

Let me know if it works or you want another explanation! 🙂

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[tooth knockn]

Can you take a pic of how the hand is suppose to be positioned.

 

[tooth knockn]

Hey guys,

I wanted to share this helpful trick to rememember some of the trig on the unit circle. I think it's the only thing I ever retained from my geometry class haha! It's takes some effort to grasp, but once you do, it's so easy to whiz by many of the trig questions, and heaven knows we already have too much too memorize.

1) Put your hand out in front of you palm facing up, I generally use my left hand. Each finger corresponds to an angle:
Pinky - 0
Ring - 30
Middle - 45
Index - 60
Thumb - 90

2) To figure out the number value for sin, cos, or tangent for an angle, fold down the finger for that angle.
So if I wanted to find a sin, cos, or tan value for 30 degrees, I fold my ring finger.

3) SIN: The sin value will be: sqrt(fingers below the folded finger)/2. In this case, if I fold down my ring finger, I have one finger "unfolded" below it, so sqrt(1)/2 = 1/2 = sin30

4) COS: The cos value will be: sqrt(fingers above the folded finger)/2. If I fold my 30 degree finger, I have 3 fingers above my folded finger, so sqrt(3)/2 = cos30

5) TAN: For tan, flip your whole hand over so palm is facing away from you with the ring finger still folded. The tan of 30 degrees will be: sqrt(fingers on top of folded finger)/sqrt(fingers below the folded finger). In this case, sqrt(1)/sqrt(3) = 1/sqrt(3) = tan30.

I know it looks complicated but I promise if you put 10 minutes of effort into memorizing it, it will be so much easier to recall simple values not only for the DAT but for the rest of your life. (Not that you need to, but hey it's a neat http://www.vbulletin.org/forum/misc.php?do=bbcode#sparty trick.)

Let me know if it works or you want another explanation! 🙂

Are you trying to make me do some type of gang signs....?

Wth

Fellow test takers will think I am cripping

 

[LightAtTheEnd]

Assuming left hand:

Edit: haha! thanks for the much needed comic relief.

 

[Davyyjoness]

Sin 90 doesn't work am I correct?

 

[Dental786]

Sin 90 doesn't work am I correct?

I believe it does.

Put your left hand in front of you with your palm facing up. Put your thumb down and you will see four fingers below your thumb. The square root of 4 is 2 / 2 which is 1. sin 90= 1.