The terms perpendicular and base are sometimes used for the opposite and adjacent sides respectively. Many people find it easy to remember what sides of the right triangle are equal to sine, cosine, or tangent, by memorizing the word SOH-CAH-TOA

The sine (sin for short) of angle A is equal to the length of the opposite side divided by the length of the hypotenuse. (Remembered via "SOH".)

The cosine (cos for short) of angle A is equal to the length of the adjacent side divided by the length of the hypotenuse. (Remembered via "CAH".)

The tangent (tan for short) of angle A is equal to the length of the opposite side divided by the length of the adjacent. (Remembered via "TOA".)

Thats where "SOH-CAH-TOA" comes from.

Note that angle A can be moved to the top right of the triangle. That would mean the adjacent and opposite sides would be switched. (Fairly obviously, the "opposite" side is always the side opposite to the angle under consideration.)

I clicked on this thread thinking 'I know I made an absolutely AWESOME joke about SOHCAHTOA a week or so ago, and everyone basically laughed for hours and now I can tell everyone!' except I can't actually remember it now.

Trigonometry jokes: SOH easy to forget! I CAHn't remember it! TOAttally wired!

Trigomometry originated as the study of certain mathematical relations originally defined in terms of the angles and sides of a right triangle, i.e., one containing a right angle (90°). Six basic relations, or trigonometric functions, are defined. If A, B, and C are the measures of the angles of a right triangle (C=90°) and a, b, and c are the lengths of the respective sides opposite these angles, then the six functions are expressed for one of the acute angles, say A, as various ratios of the opposite side (a), the adjacent side (b), and the hypotenuse (c), as set out in the table. Although the actual lengths of the sides of a right triangle may have any values, the ratios of the lengths will be the same for all similar right triangles, large or small; these ratios depend only on the angles and not on the actual lengths. The functions occur in pairs—sine and cosine, tangent and cotangent, secant and cosecant—called cofunctions. In equations they are usually represented as sin, cos, tan, cot, sec, and csc. Since in ordinary (Euclidean) plane geometry the sum of the angles of a triangle is 180°, angles A and B must add up to 90° and therefore are complementary angles. From the definitions of the functions, it may be seen that sin B=cos A, cos B=sin A, tan B=cot A, and sec B=csc A; in general, the function of an angle is equal to the cofunction of its complement. Since the hypotenuse (c), is always the longest side of a right triangle, the values of the sine and cosine are always between zero and one, the values of the secant and cosecant are always equal to or greater than one, and the values of the tangent and cotangent are unbounded, increasing from zero without limit.

For certain special right triangles the values of the functions may be calculated easily; e.g., in a right triangle whose acute angles are 30° and 60° the sides are in the ratio 1 : : 2, so that sin 30°=cos 60°=1/2, cos 30°=sin 60°=/2, tan 30°=cot 60°=1/, cot 30°=tan 60°=, sec 30°=csc 60°=2/, and csc 30°=sec 60°=2. For other angles, the values of the trigonometric functions are usually found from a set of tables or a scientific calculator. For the limiting values of 0° and 90°, the length of one side of the triangle approaches zero while the other approaches that of the hypotenuse, resulting in the values sin 0°=cos 90°=0, cos 0°=sin 90°=1, tan 0°=cot 90°=0, and sec 0°=csc 90°=1; since division by zero is undefined, cot 0°, tan 90°, csc 0°, and sec 90° are all undefined, having infinitely large values.

A general triangle, not necessarily containing a right angle, can also be analyzed by means of trigonometry, and various relationships are found to exist between the sides and angles of the general triangle. For example, in any plane triangle a/sin A=b/sin B=c/sin C. This relationship is known as the Law of Sines. The related Law of Cosines holds that a2=b2+c2-2bc cosA and the Law of Tangents holds that (a-b)/(a+b)=[tan 1/2(A-B)]/[tan 1/2(A+B)]. Each of the trigonometric functions can be represented by an infinite series.

I can't because I don't start my job til the first of may. But what I CAN tell you, is that I will need to apply it to lighting schemes. Yep. That's about all I know. Luckily this is only a small part of my job.....AND it's a trainee position :S

Trigonometry will be better taught to you by a book. You've probably got enough time for the library to order one in for you, e.g. Trigonometry for Dummies almost certainly exists, or certainly Mathematics for Dummies.

## Its about triangles...

you can come to mine and ill teach you the rest if you want.

## that's kind....

you live far away, though :)

## it's okay

i'll live wherever you want me to

## SOHCAHTOA

## OKIDONTGETIT

## WOWYOUNEEDTUTOREDINTRIG

## IKNOWITSREALLYABITMAD!

## SORRYICANTHELPYOUTHERE

I've forgotten everything about trig since last summer :(

And me the best mathematician in the year like!

## !

The terms perpendicular and base are sometimes used for the opposite and adjacent sides respectively. Many people find it easy to remember what sides of the right triangle are equal to sine, cosine, or tangent, by memorizing the word SOH-CAH-TOA

## Trigonometry

AKA

Trigger on o'merty

To solve the problem of Trigger on o'merty procced by lifting Trigger adjacent to o'metry and toss im at an angle of 75degrees

## Omg, I know trigonometry!

It must be a sin.

## a sin?

## You pronounce it like "sign" in trigonometry

It's a really clever play on words.

## Oh.....I get it :D

## csc? =

1/sin?, yeah?

## Oh fuck don't start me on those

Cos learning all those was a sin!

## What do you need to know?

## everything, basically :(

and I have 2 weeks in which to learn it :(

## What for?

## work.

## The thing is

"everything" is quite a lot, and you probably don't need to know *everything*.

Lesson 1, though: right-angled triangles.

http://www.mathsrevision.net/gcse/trig.gif

The longest side is always the "hypotenuse".

The sine (sin for short) of angle A is equal to the length of the opposite side divided by the length of the hypotenuse. (Remembered via "SOH".)

The cosine (cos for short) of angle A is equal to the length of the adjacent side divided by the length of the hypotenuse. (Remembered via "CAH".)

The tangent (tan for short) of angle A is equal to the length of the opposite side divided by the length of the adjacent. (Remembered via "TOA".)

Thats where "SOH-CAH-TOA" comes from.

Note that angle A can be moved to the top right of the triangle. That would mean the adjacent and opposite sides would be switched. (Fairly obviously, the "opposite" side is always the side opposite to the angle under consideration.)

## <3

thanx :)

## Um

Maybe try to find some GCSE revision resources? e.g.

http://www.bbc.co.uk/schools/gcsebitesize/maths/shapes/

## Haha

I clicked on this thread thinking 'I know I made an absolutely AWESOME joke about SOHCAHTOA a week or so ago, and everyone basically laughed for hours and now I can tell everyone!' except I can't actually remember it now.

Trigonometry jokes: SOH easy to forget! I CAHn't remember it! TOAttally wired!

## :D

## Are they easier to remember?

## Remind me not to invite you to do an after-dinner speech anytime.

## My turn: f(x) walks into a bar.

The bartender says "I don't serve for functions."

http://simple.wikipedia.org/wiki/Function_(mathematics)

## I really wanted that to be a 'special fx' joke.

As it is, I really wish I didn't find it funny. You bugger.

## speaking of 'not funny'

What do you get if you cross a mountaineer with a mosquito?

Nothing. You can't cross a scalar with a vector.

http://en.wikipedia.org/wiki/Cross_product

## Simple really........

Trigomometry originated as the study of certain mathematical relations originally defined in terms of the angles and sides of a right triangle, i.e., one containing a right angle (90°). Six basic relations, or trigonometric functions, are defined. If A, B, and C are the measures of the angles of a right triangle (C=90°) and a, b, and c are the lengths of the respective sides opposite these angles, then the six functions are expressed for one of the acute angles, say A, as various ratios of the opposite side (a), the adjacent side (b), and the hypotenuse (c), as set out in the table. Although the actual lengths of the sides of a right triangle may have any values, the ratios of the lengths will be the same for all similar right triangles, large or small; these ratios depend only on the angles and not on the actual lengths. The functions occur in pairs—sine and cosine, tangent and cotangent, secant and cosecant—called cofunctions. In equations they are usually represented as sin, cos, tan, cot, sec, and csc. Since in ordinary (Euclidean) plane geometry the sum of the angles of a triangle is 180°, angles A and B must add up to 90° and therefore are complementary angles. From the definitions of the functions, it may be seen that sin B=cos A, cos B=sin A, tan B=cot A, and sec B=csc A; in general, the function of an angle is equal to the cofunction of its complement. Since the hypotenuse (c), is always the longest side of a right triangle, the values of the sine and cosine are always between zero and one, the values of the secant and cosecant are always equal to or greater than one, and the values of the tangent and cotangent are unbounded, increasing from zero without limit.

For certain special right triangles the values of the functions may be calculated easily; e.g., in a right triangle whose acute angles are 30° and 60° the sides are in the ratio 1 : : 2, so that sin 30°=cos 60°=1/2, cos 30°=sin 60°=/2, tan 30°=cot 60°=1/, cot 30°=tan 60°=, sec 30°=csc 60°=2/, and csc 30°=sec 60°=2. For other angles, the values of the trigonometric functions are usually found from a set of tables or a scientific calculator. For the limiting values of 0° and 90°, the length of one side of the triangle approaches zero while the other approaches that of the hypotenuse, resulting in the values sin 0°=cos 90°=0, cos 0°=sin 90°=1, tan 0°=cot 90°=0, and sec 0°=csc 90°=1; since division by zero is undefined, cot 0°, tan 90°, csc 0°, and sec 90° are all undefined, having infinitely large values.

A general triangle, not necessarily containing a right angle, can also be analyzed by means of trigonometry, and various relationships are found to exist between the sides and angles of the general triangle. For example, in any plane triangle a/sin A=b/sin B=c/sin C. This relationship is known as the Law of Sines. The related Law of Cosines holds that a2=b2+c2-2bc cosA and the Law of Tangents holds that (a-b)/(a+b)=[tan 1/2(A-B)]/[tan 1/2(A+B)]. Each of the trigonometric functions can be represented by an infinite series.

## thatsmarvellous

but i asked about trig, not copypastefromwiki.

## Trig was the thick one.

He called Rodney 'Dave'.

You're welcome.

## very good :D

## Oh that! No, just a few things that I remembered

from a 4th form maths class...obviously, I used to use America spelling back then.

Crazy days.

## trigonometry is overated

don't believe the hypotenuse

## Very acute.

## I've reason to believe that this pun works on two levels.

I'd explain them both, but then I'd have to kill you.

## No need to be obtuse

## *American

## It's really easy.

Take three edges of a triangle to be called A, B and C. The angle between B and C is a, Between A and C is b etc

The sine of and angle is the ratio of the opposite side to the hypotenuse of the triangle.

A divided by the Sine of a is equal to B divided by the Sine of b and to C divided by the Sine of c.

In a right angled triangle, the length of the hypotenuse squared is equal to the length of the two other sides squared.

moar?

## i think i have trig dyslexia.

## Give

us an example of the stuff you need to know!

## Well,

I can't because I don't start my job til the first of may. But what I CAN tell you, is that I will need to apply it to lighting schemes. Yep. That's about all I know. Luckily this is only a small part of my job.....AND it's a trainee position :S

## The angle of relflection is equal to the angle of incidence

That's kind of important.

Trigonometry will be better taught to you by a book. You've probably got enough time for the library to order one in for you, e.g. Trigonometry for Dummies almost certainly exists, or certainly Mathematics for Dummies.

## no

Trig is best taught in person.

I'd volunteer, but the commute would kill me.

## Well I meant rather than getting us to try to teach it on a board...

But also a book is a good basis for learning stuff and then getting others to show it to you.

## thanks :)

<3

## DID YOU GET OUT OF THE WRONG SIDE OF THE BED THISMORNING?

## YOU'D BE SURPRISED

didn't mean to shout that :D