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After how many days will there be 12 hours of sunlight for the first time during the year?

After how many days will there be 12 hours of sunlight for the first time during the-example-1
User Krisdestruction
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1 Answer

17 votes
17 votes

In order to have 12 hours of sunlight, the value of the sine will need to be zero, this way S(t) = 12.

The sine can be zero when the argument is 0 or the argument is pi:


\begin{gathered} \sin(0)=0 \\ \sin(\pi)=0 \end{gathered}

Since sin(0) is the first day of the year (t = 0), let's use sin(pi):


\begin{gathered} S(t)=12+2\sin((2\pi)/(365)t)\\ \\ S(t)=12\\ \\ 2\sin((2\pi)/(365)t)=0\\ \\ (2\pi)/(365)t=\pi\\ \\ (2)/(365)t=1\\ \\ t=(365)/(2) \end{gathered}

Therefore the correct option is the second one.

User Ian Flynn
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