# Sinusoidal models word problems

Solve word problems that involve real-world contexts that are modeled by sinusoidal functions.
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### Problem

I, left parenthesis, t, right parenthesis models the daily solar irradiance, measured in start fraction, k, W, h, divided by, m, start superscript, 2, end superscript, negative, d, a, y, end fraction, on a farm, t days after the summer solstice. Here, t is entered in radians.
I, left parenthesis, t, right parenthesis, equals, 1, point, 5, cosine, left parenthesis, start fraction, 2, pi, divided by, 365, end fraction, t, right parenthesis, plus, 4, point, 3
What is the second time after the summer solstice that the solar irradiance is 5, point, 2, start fraction, k, W, h, divided by, m, start superscript, 2, end superscript, negative, d, a, y, end fraction?