Answer:
9.3 hours
Step-by-step explanation:
Given
[tex]y = 2.89\sin(0.0145x-1.40) + 10.99.[/tex]
Required
Hours of sunlight on Feb 21, 2013
First, calculate the number of days from Jan 1, 2013 to Feb 21, 2013
[tex]days = 52[/tex]
So:
[tex]x = 52[/tex]
So, we have:
[tex]y = 2.89\sin(0.0145x-1.40) + 10.99.[/tex]
[tex]y = 2.89\sin(0.0145*52-1.40) + 10.99.[/tex]
[tex]y = 2.89\sin(0.754-1.40) + 10.99.[/tex]
[tex]y = 2.89\sin(-0.646) + 10.99.[/tex]
[tex]y = 2.89*-0.6020 + 10.99.[/tex]
[tex]y = -1.740 + 10.99.[/tex]
[tex]y = 9.25[/tex]
[tex]y = 9.3[/tex] --- approximated