00:01
Okay, so you want to find where the temperature is 37 .28, and we have the equation as 37 .1 plus 1 .4, sign of pi over 24t, cosine of pi over 24t.
00:24
So first step is subtract 37 .1, and we are left with 0 .18.
00:35
And then divide that by 1 .4.
00:43
And as a fraction that is 9 over 70.
00:49
And this is sine of pi over 24t, cosine of pi over 24t.
01:02
So we can use an identity.
01:10
So sine of 2 theta is equal to to 2 times sine of theta, cosine of theta.
01:36
So from here we can see that sine of theta, cosine of theta is 1 half, sine of 2 theta.
01:43
So this is 9 over 70, 1 half sign of 2 pi over 24t, which is pi over 12.
01:59
Multiply both sides by 2, and we get 18 over 7.
02:03
Which reduces to 9 over 35 and we'll leave it as 18 over 70.
02:14
Sign of pi over 12t.
02:17
We can take the inverse sign of both sides...