00:02
Okay, this is question 47, page 78, lesson 14, 2.
00:08
And when you see these sorts of things, it's really important, i think, that you get into the habit of underlining important words.
00:16
We need complete solutions, radiance, answer, and radiance, of this equation there.
00:24
Okay? so the first thing i'm going to do is, i don't want sign and cosine both in the same equation.
00:32
I'm going to use one of my trade identities and find out what cosine actually equals or close squared equals.
00:40
And the trade identity says that co squared equals 1 minus sine squared.
00:46
Good.
00:46
Now i'm only dealing with sign squared.
00:49
And i'm going to bring the minus 1 there because it doesn't have a sign in it.
00:53
And i'm going to bring the sign squared over to that side.
00:56
And please remember that when you change sides, you also change the sign.
01:03
And i've also thrown ones and ones in there just to remind you that they are one sign squared...
