00:01
In this question, they say the amount of sunlight in a certain city can be modeled by the function h, which is 15 times the cosine of 1 over 600 times d, where h represents the hours of sunlight and d is the day of the year.
00:14
I'm going to use the equation to find how many hours of sunlight there are on february 10th, which is the 42nd day of the year.
00:22
I'm going to state the period of the function.
00:25
So if d is 42, i'm trying to figure out what h is.
00:30
And so i'm going to just plug in, i have h equals 15 times the cosine of 1 over 600 times 42.
00:41
And so we're going to head to a calculator.
00:43
We're going to say, make sure you are in radian mode, first of all.
00:47
So i'm radian mode.
00:49
I have 15 times the cosine of 42 over 600, 15 times the cosine of 42 over 600.
01:00
And i get 14 .963.
01:07
So we're going to have 14 .963...