00:01
We now determine the value of sine of 7 pi over 6 and cosine of 7 pi over 6 without using a calculator.
00:07
So first i'm going to write this angle, 7 pi over 6 as a sum of an angle plus the reference angle.
00:14
So this can be written as 7 pi over 6.
00:17
The sound pi can be written as 6 pi plus pi and divided by 6.
00:23
So this equals 6 pi over 6 plus pi over 6.
00:28
So this equals we cancel the 6.
00:31
So this is equivalent to pi plus pi over 6.
00:35
So we have written this 7 pi over 6 as a sum of an angle which is pi plus the another angle that is pi over 6.
00:46
So this pi over 6 is basically the reference angle because this is less than 90 degree or pi by 2.
00:54
So we now determine the sign of 7 pi over 6.
00:59
So therefore we can take sign on both sides.
01:02
So this becomes a sign of 7 pi over 6...