00:01
Okay, let's use a pythagorean identity here.
00:02
What's a pythagorean identity? well, the first one is sine squared plus cosine squared equals one.
00:09
To find an equivalent form, what i could do is divide this all, well, this is the first identity, so let's use this.
00:16
Okay, so we know that sine of theta is three, negative three over five, so i'm going to replace this with negative three over five squared.
00:23
I don't know what cosine squared is, equals one, and try to solve this.
00:28
So negative three over five squared, what's negative three times negative three? positive nine, five times five is 25, plus cosine squared of theta equals one.
00:38
But i have a denominator of 25.
00:40
What i'm going to do is multiply this one by 25 over 25 to get the same denominator.
00:48
So nine over 25 plus cosine squared of theta equals 25 over 25...