trigonomitry

[Sophie 378]

how in the world do you do trigonomitry?

its extremly confuseing the thing about finding the right function

SOH - CAH - TOA. Remember that.

That's pretty much it ... just keep chanting "soh-cah-toa" until it sticks in your mind, the same for Pythagoras, and make sure you can always identify the hypotenuse/adjacent/opposite of any given triangle. Then you can work out whatever they're asking you.

 

[brennan]

1) Take a right angled triangle (one with a 90 degree angle in it). The side opposite the right angle is always the longest and is called the Hypoteneuse (H).

2) We can pick either of the two other angles to work with when we make a calculation. Whichever one we pick, the angle is made by the Hypoteneuse and a side that we refer to as the Adjacent (A). The remaining side is called the Opposite (O). Note that these labels (O & A) change around depending on which angle you are using.

3) The trigonometric functions that let us utilise these sides and angles are Sine (sin), Cosine (cos) and Tangent (tan). You won't have to know how to work these out, because they are helpful little buttons on your calculator.

Silly old Harry is my favourite way of remembering how the letters are laid out in the three basic trig formulae: SOH CAH TOA. Some people just remember the word sohcahtoa.

To work out any unknown, you need any 2 knowns: let's take SOH as an example:

S) You know the Hypoteneuse (H) and one other side (which will be O). You can work out the sine of the angle Opposite these two sides by dividing O by H. To find out what the angle actually is, do the division, then press the inverse sine button (sin^-1) - it might be that you have to use Shift+sin. Sine of angle = O/H, angle = sin^-1 (O/H)

O) You know An angle and the Hyponeneuse. You can work out the length of the Opposite side by taking the sine of the angle (enter the angle in calculator and press sin) and multiplying it by H. O= sin(angle)*H

H) You know an angle and the Opposite side. To determine the length of the Hyp, divide the length of the Opposite by the sine of the angle. How to do this will vary with your calculator, on mine I enter the Length, press divide and then enter the angle and press sin (without pressing =) this converts the angle into it's sine value, then I press = to complete the division and obtain the desired Length of H. H=O/sin(angle)

 

[Fugitive Sisyphus]

soh-cah-toa

I memorized it as "Some Old Hippy Caught Another Hippy Tripping On Acid"

 

[Phlegmak]

how in the world do you do trigonomitry?

Well, you get a textbook on it and learn it.

 

[StarWorms]

Remember the sine and cosine rules...

Sin rule: a/SinA = b/SinB = c/SinC

Cos rule: a^2= b^2 + c^2 - 2bcCosA

 

[ybbor]

are you also expected to know the unit circle?

 

[Cheezy the Wiz]

soh-cah-toa

I memorized it as "Some Old Hippy Caught Another Hippy Tripping On Acid"

I learned "Oscar Had A Hunk Of Ass."

 

[Sidhe]

Silly
Old
Harry

Caught
A
Herring

Trawling
Off
Afghanistan.

Isn't it amazing that even twenty years later I still remember that mnemonic. Although the country changes with the politics.

 

[kristopherb]

thanks it helped me lots thanks

 

[silver 2039]

Do you need Sin law or Cos law?

 

[Sidhe]

Do you need Sin law or Cos law?

I've only used it in A' level mathematics, or physics to produce triangulation of forces answers. But GCSE's may have changed since my day. We only used SOH CAH TOA in my day. This was the year they ditched O' levels, which were much harder IMO. Having looked at both papers, they had a lot of what we would consider A'level stuff now. So it depends how much maths was dummed down or souped up in your clasess. I supose AP maths would go into it?

 

[nonconformist]

I've only used it in A' level mathematics, or physics to produce triangulation of forces answers. But GCSE's may have changed since my day. We only used SOH CAH TOA in my day. This was the year they ditched O' levels, which were much harder IMO. Having looked at both papers, they had a lot of what we would consider A'level stuff now. So it depends how much maths was dummed down or souped up in your clasess. I supose AP maths would go into it?

Nah, you can get through GCSE withoutit no probs.

Or I did, anyway.

 

[Eukaryote]

Don't ask me, I don't even know what it is. Which leaves the question, why did I post here?

 

[Sidhe]

Don't ask me, I don't even know what it is. Which leaves the question, why did I post here?

To increase not only your post count but the post count of the person who pointed it out thus making said person a hypocrite? My theory anyway?

Noted for future referance we will not ask Drool4Res-pect about trigonometry, thanks

Nah, you can get through GCSE withoutit no probs.

Or I did, anyway.

Still a doddle then GCSE maths. That's nice

 

[Heretic_Cata]

Holy mother of God. You people are crazy.

At least someone knows how trigonometry should be thaught/learned :

But i do see some things that i never heard of on the pic.

 

[nonconformist]

Holy mother of God. You people are crazy.

At least someone knows how trigonometry should be thaught/learned :

But i do see some things that i never heard of on the pic.

They're all functions defined as being function of cos, sin and tan.
Tan, for example is
Cos/sine

I think cot is sine/cos.

 

[Heretic_Cata]

They're all functions defined as being function of cos, sin and tan.
Tan, for example is
Cos/sine

I think cot is sine/cos.

The things i've never heard of are: csc,versin,exsec,sec.
Or maybe they have wierd names in Romanian .

 

[Ansar]

Is Trigonometry the same as Pre-Calculus?

 

[-0blivion-]

Noncon, Tan = Sin/Cos and Cot = Cos/Sin

 

[Tomoyo]

When I learned about trigonometric functions, I never saw that diagram. We used a two-unit circle on an x-y coordinate system, with perpendiculars to the x-axis drawn from various points in each quadrant. Then we identified the x, y, and r (radius) of each point on the circle and defined sine, cosine, and tangent in terms of x, y, and r. Then we were told about csc = 1/sin, sec = 1/cos, and cot = 1/tan.

Then we were made to memorize twenty-something formulas.

Now what's a versine?