00:01
Of this function on the interval zero to pi over three.
00:05
So we need to find the derivative, y prime, square to two, minus the derivative of the secant is secant tangent.
00:15
So we need to find where this derivative is zero and where it's undefined.
00:19
Well, sicken and tangent both have cosine in the denominator, so it's undefined at odd multiples of pi over two, and none of them are in there.
00:29
So we don't have to worry about that.
00:30
All we have to do is worry about where it equals zero.
00:36
Okay, so here's my first thought.
00:42
Okay, that gets me nowhere.
00:44
So i'm going to go ahead and switch to sign and cosine and see if that will help.
00:49
Seekin is 1 over cosine, tangent is sine over cosine.
00:52
So i get sign over cosine squared equals square root of 2 over 1.
01:03
So i cross multiply, whoops, and i get sign equals square root of 2.
01:11
2 cosine squared.
01:18
Okay, that's not helping any.
01:19
So now i'm going to take out the cosign squared and i'm going to put in 1 minus sine squared because then i'll have only signs and i'll have a quadratic equation which i will try to solve.
01:31
Okay, so i get square to 2, sine squared theta, plus sine theta minus the square root of 2 equals 0...