00:01
Okay, here we have f of theta.
00:04
It's just tan theta defined on the interval negative pi over 3 to pi over 4.
00:18
And recall that tan will be continuous because this interval lies between one of its periods, negative pi over 2 to pi over 2.
00:28
Okay, so we have an absolute max in men.
00:31
And so if we find the critical points, 2 squared theta, the second square theta is never equal to zero.
00:45
It's also never, well, it's going to be undefined when cosine is zero, but that's exactly when tan is undefined.
00:54
So in this interval, the derivative is actually going to be not only just not zero, it's going to be strictly positive and finite.
01:05
So it's just going to, this is saying because the derivative is positive here, tangent is increasing.
01:12
But the point is we have no critical.
01:13
Points and again i mean secan squared is 1 over cosine squared the only way a a fraction can be 0 is if the numerator is 0 okay so we just need to test the endpoints so tangent of negative pi over 3 that is going to be negative 1 over root 3 believe and then tangent of pi over 4 is 1 so this is the absolute men at negative pi over 3 is the opposite max.
02:02
Okay, looks good.
02:16
Actually, no, this isn't correct.
02:20
Double check my trigly.
02:23
So yeah, tangent of negative pi over 3 is cosine of negative pi over 3 over sorry, sign of negative pi over 3 over cosine negative pi over 3.
02:35
And so that's negative root 3 over 2 over 1 half, which is root 3...