Thread: A stupid question.

A question to non-Russians. I've read some article. I don't believe it, but... it really awoke my interest. Strong interest. I know that my doubt may offend you, but I can't suffer any more. Execuse me, if you find my question insulting.

OK, here's the most stupid question I've ever asked:
Do you know why sin30 = 0,5?

Um...this is a mathematical operation.

The sine (abbreviated "sin") of an angle measurement of 30 degrees is equal to 0.5

sin(30)=0.5

This is the only way I can make sense of that....

LOL...how did you come about this?

sin(30) = 0.5

The sine of a 30 degree angle is 0.5.
That means if you shoot something at a 30 degree angle, the height attained is half of the distance covered. (But that is assuming there is no gravity.)

Because, my friend, when a triangle has the angle of 30 degrees, the hypotenus is double as long as the opposite! ALWAYS! And then the ratio will always be 1/2!

sin X = Opposite / Hypotenus

PS: Opposite is the line which is opposite the angle X and hypotenus is that really long line opposite the 90 deg

I am impressed with your math skills!

Well, it is kind of my job to know math... :P

Anyway, how do you spell sinus / sine / sin in Russian? Do you use latin letters or what?

синус

Ha! That was on my Algebra final this year! SohCahToa! I think, I can't remember. I wrote it on my hand.

SohCahToa is what got me through those courses...I can never forget it.

I miss my Algebra class! I had so much fun there! Even if I can't really remember much. -Wipes tear-

Edit:
Why am I capitalizing Algebra?

Вопрос, видимо, навеян этой статьёй
http://nauka.relis.ru/05/0412/05412020.htm

sin X = Opposite / Hypotenus

OK, kalinka, what must I do when X > 180? sin270 = -1, but can you give me a triangle with 270 degrees angle?

Originally Posted by N

Вопрос, видимо, навеян этой статьёй
http://nauka.relis.ru/05/0412/05412020.htm

You're right!
But just understand, I don't want to offend somebody. The article describes such fantastic things, unbelievable things! So unbelievable for me, that my interest doesn't allow me to be calm!

Sorry Pranky but when they started to mix numbers with the alphabet they lost me.

Originally Posted by pranki

sin X = Opposite / Hypotenus

OK, kalinka, what must I do when X > 180? sin270 = -1, but can you give me a triangle with 270 degrees angle?

Well, ok, this method it only works for < 90 degrees

For larger values... you have to learn... the... dreaded... UNIT CIRCLE (dramatic music)



Hint: - If you are doing a sine of the angle, look for the intersection from the unit circle's circumfrance to the vertical line (for cosinus to the horizontal line)

kalinka, you're quite right!!! Now I know, that the article lies!

But let's think about the following. How does your calculator get values of sine? Does it draw the unit circle (thanks for the term, I didn't know how does единичная окружность sound in English) in its memory, look for intersections etc?

Originally Posted by pranki

The article describes such fantastic things, unbelievable things! So unbelievable for me, that my interest doesn't allow me to be calm!

What's so unbelievable about it? *Shrug*

Originally Posted by pranki

kalinka, you're quite right!!! Now I know, that the article lies!

But let's think about the following. How does your calculator get values of sine? Does it draw the unit circle (thanks for the term, I didn't know how does единичная окружность sound in English) in its memory, look for intersections etc?

pranki, do _you_ really know how exactly it gets the values? i suspect it might well depend on the calculator (unless there is one cheap chinese chip that everyone uses)

Originally Posted by laxxy

pranki, do _you_ really know how exactly it gets the values? i suspect it might well depend on the calculator (unless there is one cheap chinese chip that everyone uses)

I just wanted to get the most common definition of sine.

OK, I call off my last question. It isn't fairly, because it is learned in univesity departments, which are dedicated to mathematics, and ordinary people don't have to know this.
I'm sorry.

Aah!!! Get this crap out of my face! I had to take 22 semesters of Advanced Algebra / Advanced Calc in school! I've spent years erasing this all from my memory!
-Fantom

ps- TriggerHappyJack, I have the habit of capitalizing Algebra and Calc also, maybe it's our nature to capitalize things that suck a lot...!