Why are Sine & Cosine given their names?

[jasonjackson]

Wait! Come back! What is TanX?! Wow, what a cliffhanger!

[louf]

Cosine: complement of sine.
Thank you.

[davepubliday]

Sine (sin) comes from “sinus” in Latin meaning bend fold or curve. This is so named because the sin math function comes to us through Arabic scholars who called it “jaib”, which is Arabic for “bosom”. They called it that because that Arabic word sounded like the Sanskrit word “jiva”. Jiva is Sanskrit for chord. The ancient Indians called it a chord.

[benheideveld]

Sinus is Latin, it means gulf and wave but it also means female breast. “Tangens” means “touching”. Trig can easily be made so much more interesting to teens...

[petrustefanescu]

*Casually draws a pretty good sinusoid*

[palmtrees]

Mate, your teaching is absolutely outstanding! The approach is the way it is supposed to be, really! You are a legend! Thank you so much!

[nikhilraov]

I wish I had a teacher like u . U just inspire

[palmtrees]

Your teaching is so inspiring! It breaths in practical way of thinking! You remind us that math makes sense, and that there is no point in learning on heart!

[UFOENGINE]

You are wrong. Sine's etymology dates back from the ancient Indian word in Sanskrit which is jyā. Then in 10th century mathematics took off in the middle east and this term was adopted by the Islamic scholars which then has been translated from ancient Indian texts from Sanskrit to Arabic as jība. When mathetmatics took off in western Europe (around 1200s), the European scholars went to Madrid (which was islamic at that time) and copied texts from Arabic to Latin which then they made a CURIOUS mistake. When they came across the word  jība, they couldn't find any word jība in the Arabic language and they thought that jība is a grammar mistake for the word jaib, which in Latin is 'sinus' (english - 'sin') and it means 'harbor'. Then for the cosine people gave it the name as the companion length of the sine thus cosine.

[mandharjoshi]

actually there is a small addition to the sine theory . the reall word was "jaya" and it was invented by aryabhatta who was an indian mathematician . "jaya " meant "half chord " and was hence used in astronomy . also the jaya was then came to be known as "bosom " which is how the arabians called it but then the europeans mistook the word as chord and then they named it as "sinus" which is an latin word . then it was came to be known as sine by the english . i hope this is informative :) :)

[kabayanhustler]

Sine: Hi Cosine! How ya doin?
Cosine: Oh Hi Sine, Nice Haircut!

[davidlloyd]

SOH CAH TOA - remember that from high school 40 years ago. Sine = Opposite over Hypotenuse, Cosine = Adjacent over Hypotenuse etc. Useful acronym.

[Slarti]

Very interesting.
Having been born in 1970, I remember at school having a book that contained tables for sin and cosine values. When we did geometry we had to use these tables.
We were banned from using calculators for the first five years of doing maths.

[briancox]

Extremely articulate voice! Very easy to listen to. Great teacher!

[ccbabu]

The way of approach is very fundamental and original;
Clarity of thought and enthusiastic to Teach with complete didactics!
Thanks a lot !

[StevenTorrey]

"I talk with a funny accent." "No, you listen funny!"

[shaktigg]

from wiki
Etymologically, the word sine derives from the Sanskrit word for chord,  jiva*(jya being its more popular synonym). This was transliterated in Arabic as jiba جيب, which however is meaningless in that language and abbreviated jb جب . Since Arabic is written without short vowels, "jb" was interpreted as the word jaib جيب, which means "bosom". When the Arabic texts were translated in the 12th century into Latin by Gerard of Cremona, he used the Latin equivalent for "bosom",  sinus (which means "bosom" or "bay" or "fold").[12][13] Gerard was probably not the first scholar to use this translation; Robert of Chester appears to have preceded him and there is evidence of even earlier usage.[14] The English form sine was introduced in the 1590s.

[spacetimemalleable]

It is teacher's like Ed Woo that keeps Math alive and well in the world. We need to have much more teacher's like Ed who inspire and get people interested in this exceedingly important subject.

[paoloctsi]

I truly respect your teaching attitude. I wish I can teach as good as you teach.

[ryanjohnson]

Never thought I’d be watching a math video for fun XD