Sin Cos Tan

對於30,45,60要重點去計，而0,90,180,270,360呢幾個度數就從圖像上去計ok？？
30 45 60
sin 1/2 √2/2 √3/2
cos √3/2 √2/2 1/2
tan √3/3 1 √3

sin30=cos60 sin45=cos45 sin60=cos30對應噶！可以記一個sin就得
不過以下呢部份最好就從圖像方面去記...容易好多...
sin0=sin180=sin360=0
sin90=1, sin270=-1
cos0=cos360=1
cos90=cos270=0
cos180=-1
嘗試下啊...maths is so fun, try your best and enjoy it!!

Do you mean this?

http://hk.knowledge.yahoo.com/question/question?qid=7007081003096

Amazing!

其實如果你地講果D
我都知左好耐.
我係想問如果有D係26度, 89度果一種- -"

three steps
1. draw a table
30 45 60
sin
cos

2. filll the table with sqrt 1, sqrt 2, sqrt 3 as below
30 45 60
sin sqrt(1) sqrt(2) sqrt(3)
cos sqrt(3) sqrt(2) sqrt(1)

3. complete the table divide by 2
30 45 60
sin sqrt(1)/2 sqrt(2)/2 sqrt(3)/2
cos sqrt(3)/2 sqrt(2)/2 sqrt(1)/2

remember sqrt(1) = 1
tan A = sin A / cos A
thus, tan 30 = sin 30 / cos 30 = (1/2) / (sqrt(3)/2) = 1 / sqrt(3)

有d係指定有得背,好易記,例如
sin 0,90,180,270,360=0,1,0,-1.0...

有啲度數唔需要用計算機，例如0，30，45，60 同 90度，背都背得出，得閒記記。