hey. i was absent for the first trig class of the year during Geometry, and now am having trouble with the homework assigned this week. how would i solve this: ------------------------------------- Express each of the following in simplest radical form: a) sin 30 degrees b) cos 30 degrees c) tan 30 degrees ------------------------------------- yes, very easy... also: ------------------------------------- Given CB=12 and AB=21, find the measure of angle B to the nearest degree. ------------------------------------- any help (and perhaps maye a little tutoring) would be greatly..and i mean GREATLY... appreciated. thanks.

sin(30) = 1/2
cos(30)= sqrt(3)/2
tan(30) =1/sqrt(3)

You can calculate these angles from a simple triangle.. whos angles are 30º, 60º and 90º. The sides of the triangle will have lengths 2(hypotanuse), 1(opposite) and sqrt(3)(adjacent) .. its quite a standard triangle that comes up very often.. and worth learning

Its easiest to explain with a diagram.. but its hard to draw on here.. so ill let u do that urself

once you know the sides of the triangle.. u can calculate the 30º angles by using the simple trig formulas

sin(angle) = opposite side/hypotanuse
cos(angle) = adjacent side/hypotanuse
tan(angle) = opposite side/adjacent side

if u stick 30 into the these formulas.. u get the results at the top(using the standard triangle which i explained)


---------------------


assuming AB CB are two sides of a right angled triangle..

where AB is the adjacent side and CB is the opposite side..

then the angle would be the inverse tan of CB/AB .. which is 29.74 degrees.. or to the nearest degree (as requested) 30º

If ive done the sides wrong.. just use the other functions.. like sin or cos to work out the angle


Hope that explains it

[edited by - quant on March 16, 2003 7:12:00 AM]

a) the forum guide to gamedev.net says no homework questions

b) there''s about 6 million web pages that address simple trig, so stfw.

what's: "stfw?" I've never seen the 'u' for "up" being replaced by a "w" for I don't know what. And I also don't see any problem that asking for homework help is causing, 'sep' YOU! Back to the basics:

The properties of 45, 45, 90, and 30, 60, 90 degree triangles were tought to me in 9th grade geometry. In a 30-60-90 triangle, the shortest leg is 1/2 the length of the hypotenuse, and the longest leg is the shortest leg multiplied by the square root of 3 (ie 3^.5). These properties, like pythagoras and his discoveries, were probably derived emperically from real-world measurements. I guess this is how those Newtons and Isacs founded everything. And it happens that the 30-60-90 properties help define the trig functions, which have no "formula," therefore they must be approximated and checked just as you would find the square root of an uncomprehensible number.

Recap:
small leg = 1/2(hypotenuse)
small leg = 3^-1/2(long leg)

long leg = 3^1/2(small leg)
long leg = 3^1/2(hypo/2)

hypo = 2(small leg)
hypo = 3^-1/2(2*long leg)

I hope I'm right on those, I just derived them. Note that multiplication was denoted with an asterisk ("*") and by parenthesis coefficients. If you don't know how to represent radicals in the exponential form, it's really easy to learn:

"sqrt(3)" == "3^1/2" Ya see what I mean? The expression can be rewritten exponentially by taking the base to the expressive one half power, or just the reciprocal of the root index. One can then deduce: 9^1/3 is the same as saying "the cube root of nine," which equals 3. If you're wondering how I made the superscripts for my exponents, click on the 'edit' button on the header of this post.

[edited by - 63616c68h on March 16, 2003 4:21:05 PM]

stfw stands for Search The Fruity Web (the F doesn''t really stand for Fruity), and means that rather than waste someone''s time, you could easily find the info you need through a web search.

---

How appropriate. You fight like a cow.

http://www.google.com/search?q=stfw&sourceid=mozilla-search&start=0&start=0

He's not wasting your time, you didn't have to post. I found this thread resourceful. It prompted me to recapitulate, myself, about what he's asking. I don't see how you'd even find time to post a rant especially during the resolve of that 500x10 epidemic.

EDIT: smartertard, don't listen to these high-and-mighty math gods that can't be bothered by our "fledgling" quandries. But next time you need help with a math homework problem you fee valid, post it under a non-homework-related title, such as: "goatse," or how about "cats and dogs and trigonometry." That should keep da shit cool

[edited by - 63616c68h on March 16, 2003 5:03:29 PM]

Knowledge is knowledge is knowledge and should never be mistaken for either intelligence nor ambition. Rather than simply telling someone I know the answer or how to find the answer and you should as well you should either hold your tongue or give some guidance. My preferance is give some guidance such as look here. You could alternatively say try searching for "Law of Sines" and "Law of Cosines" on Google.

I''ve save grhodes some time and post this myself:

quote:

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Math and Physics Forum FAQ
3. Is it acceptable to post school homework questions?

It is NOT appropriate to simply ask for answers to homework questions. Especially those where the answer involves mathematical or physics derivations. Do the work for yourself. The purpose of homework is to teach you to solve problems for yourself, and you"re cheating yourself out of an education if you choose to take the answer from someone else"s hard work and thinking. Think about it. Will you be able to pass a comprehensive in-class examination if you don"t actually learn the material by practicing to solve problems given in homework assignments? I think not.

That said, properly stated homework questions are welcome. Here are some rules. (A) Ask your peers----other students at your school----and teacher first before posting questions here. (B) This is a forum for game development, and the questions should be related somehow to math and physics in game development. Be prepared to say how your question relates to game development. (C) When asking technical questions, show your own work in detail before asking any question. (D) Never ask for the answer. Ask for a hint or suggestion on how to proceed with finding the answer for yourself.

If you are a student, then you are bound by an honor system not to cheat. Its an unwritten contract between you and your teacher and school. YOU are the loser if you break the contract. Many times, it is obvious that a question is purely and simply a homework question. But other times it is less obvious. Do the right thing for YOURSELF and don"t cheat.

---

If you don''t like it, then you don''t have to post here either. We always give people second chances, so as long as smartertard doesn''t post any more homework questions, no hard feelings.

As you can see, your flames have not turned his thread into the void. The only class of persons that has the power to do that is the moderator, so stop trashing it with negative energy and either start helping or *tab*-out and depress the *backspace* key on your keyboard To explain this concept better, I've created a little graphical demo manifesto:

GameDev Class Hierarchy

Dave || Gaiden --> Moderator(s) --> Experts(in the Field)-->

--> Contributors (to GameDev) --> Elites (with special icons)-->

--> Mainstreamers (you & me, for now...) --> Trolls

(The "-->" indicates the sense or "direction" of power. This hierarchy could be analogous with Presidential Succession[in order of creation of office, though])

Let's just say: right now, you're at the bottom of Yertle's turtle stack, Mack!


[edited by - 63616c68h on March 16, 2003 5:20:40 PM]