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Ronin · 02-06-2010, 12:02 PM

The way I can most easily remember it is, that the cousins is the projection of a straight segment onto a straight line.

The sinus is the other thing.

And as the result of the fraction is always smaller than one, the hypotenuse must always be the denominator.

XKwisite · 02-06-2010, 12:23 PM

Quote:

Originally Posted by Eferos

Very true. However, Sandman specificly said "having cheats sheets in my calculator really helped", which is suggesting that cheating is okay in his view. It was that particular phrase that I found funny.

You need to look at math objectively the reality of the situation is that if in real life you're using math to solve a problem and you can't remember that tan=sin/cos what do you do? You google it.

In my opinion so long as you know how to work out the problem without necessarily knowing every single formula you can accomplish what needs to be done.

garbanian · 02-06-2010, 12:29 PM

Quote:

Originally Posted by Eferos

Very true. However, Sandman specificly said "having cheats sheets in my calculator really helped", which is suggesting that cheating is okay in his view. It was that particular phrase that I found funny.

Some graphic calculators do have a notes feature. You can like type the shit in and save it, open it later, when needed.
That's why so many are banned from the ACT, heh.

Paladinn · 02-06-2010, 11:59 PM

I'm in Trig now, and yeah the SOH-CAH-TOA thing is what you need.
On a non right triangle (no 90 degree angles) you'll have to use the law of sines and cosines. You use them to find unknown angles.

Law of sines is when you have a ratio (angle A and side a) and either another side or angle. To find a side (let's say side b) use the formula b = (B * sin A)/sin a. To find an angle (in this example angle B ) use B = sin-1 [(b * sin A)/a]. Make sure that for the angle, you only use the inverse sin AFTER doing (b * sin A)/a.

Law of cosines is when you don't have a ratio at all (ie you have all three sides but no angles, OR two sides and one angle that doesn't match, so a, B, c).
This one's longer but actually easier, and there's three formulas to use:

a(squared) = b(squared) + c(squared) - 2bc(cosA)
b(squared) = a(squared) + c(squared) - 2ac(cosB )
c(squared) = a(squared) + b(squared) - 2ab(cosC)

Make sure that you solve it to find the side/angle you need.

blitzforce · 02-07-2010, 12:17 AM

sin(A+

= sinAcosB + cosAsinB
sin(A-

= sinAcosB - cosAsinB

cos(A+

= cosAcosB - sinAsinB
cos(A-

= cosAcosB + sinAsinB

tan(A+

= (tanA+tan

/ 1 - tanAtanB
tan(A-

= (tanA-tan

/ 1 + tanAtanB

Sandman53 · 02-07-2010, 07:46 AM

Quote:

Originally Posted by Eferos

Very true. However, Sandman specificly said "having cheats sheets in my calculator really helped", which is suggesting that cheating is okay in his view. It was that particular phrase that I found funny.

Depends. I am under the view that a teacher should give a student all of the tools that they would have available to them in those conditions. Is it easier to calculate a problem by hand or with a calculator? I mean sure knowing how the problem works and how to do by hand is important, but no one in your life is ever going to have you doing the ****in thing by hand because a calculator is faster and there is a less likely chance of ****ing up the math somewhere.

So if thats cheating... sure? My teacher allowed us to use graphics calculators in class, and if I have things to remember like hte ****in sin of a 45/45 triangle I am glad I don't have to remember it and can just pull it up. All of the actual calculations I did by hand, and used the calculator to do its calculating job where necessary.

*addon*

I'd also like to point out that a cheat sheet isnt a sheet that gives you all the answers, most people tend to use the word in this meaning: a concise set of notes used for quick reference.

Eusnon · 02-07-2010, 02:48 PM

Do you know if anything about cosecant secant and cotangent will be on it? If not

You have the easy shit and all you really need to know is your SOHCAHTOA

Really what you need to do is go find some questions online and practice them

because practice makes perfect (in math at least)

02-06-2010, 12:02 PM	#31 (permalink)
Ronin OnRPG Elite Member! Join Date: Mar 2007 Location: Hitman Victor Posts: 4,922 Reputation: 302	The way I can most easily remember it is, that the cousins is the projection of a straight segment onto a straight line. The sinus is the other thing. And as the result of the fraction is always smaller than one, the hypotenuse must always be the denominator. __________________ Stay frosty. Last edited by Ronin; 02-06-2010 at 12:05 PM.

02-06-2010, 11:59 PM	#34 (permalink)
Paladinn Illgamez Insomniac Join Date: Nov 2006 Location: The friend zone Posts: 2,325 Reputation: 126	I'm in Trig now, and yeah the SOH-CAH-TOA thing is what you need. On a non right triangle (no 90 degree angles) you'll have to use the law of sines and cosines. You use them to find unknown angles. Law of sines is when you have a ratio (angle A and side a) and either another side or angle. To find a side (let's say side b) use the formula b = *(B sin A)/sin a. To find an angle (in this example angle B ) use B = sin-1 [(b * sin A)/a].** Make sure that for the angle, you only use the inverse sin AFTER doing (b * sin A)/a. Law of cosines is when you don't have a ratio at all (ie you have all three sides but no angles, OR two sides and one angle that doesn't match, so a, B, c). This one's longer but actually easier, and there's three formulas to use: a(squared) = b(squared) + c(squared) - 2bc(cosA) b(squared) = a(squared) + c(squared) - 2ac(cosB ) c(squared) = a(squared) + b(squared) - 2ab(cosC) Make sure that you solve it to find the side/angle you need. __________________

02-07-2010, 12:17 AM	#35 (permalink)
blitzforce Raider of Empty Tombs Join Date: May 2006 Posts: 350 Reputation: 10	sin(A+ = sinAcosB + cosAsinB sin(A- = sinAcosB - cosAsinB cos(A+ = cosAcosB - sinAsinB cos(A- = cosAcosB + sinAsinB tan(A+ = (tanA+tan / 1 - tanAtanB tan(A- = (tanA-tan / 1 + tanAtanB __________________

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02-07-2010, 02:48 PM	#37 (permalink)
Eusnon Sun? What Sun? Join Date: Dec 2009 Posts: 971 Reputation: 26	Do you know if anything about cosecant secant and cotangent will be on it? If not You have the easy shit and all you really need to know is your SOHCAHTOA Really what you need to do is go find some questions online and practice them because practice makes perfect (in math at least)