The Weekly Bugle, a highly popular (fictional) newspaper in the (fictional) city of Dan Harbor, recently started a new website to boost their viewership. At its highest, their website reaches 540 viewers every Sunday at noon, and at its lowest, the website falls to only 4 viewers on Wednesdays at midnight (exactly 3.5 days later). The Bugle noticed that their website can be described well using a sinusoidal curve. Let B(t) denote the number of viewers on the Weekly Bugle's website at time t days since Tuesday, June 1st, 2021, at noon. Give a formula for a sinusoidal function that models B(t).

b) The Monthly Harpist, a different fictional newspaper in the unrelated fictional city of Fast Rapids, has also recently started a website. The number of viewers on their website at time t days since its launch is given by F(t) = 300 cos 15 (t 1) + 320 Once the Harpist's viewership falls below 400 viewers, what is the minimum number of days that need to pass until their viewership is back up above 400? Give your answer in exact form.