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Sinusoidal models word problems

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M, left parenthesis, t, right parenthesis models the distance (in millions of start text, k, m, end text) from Mars to the Sun t days after it's at its furthest point. Here, t is entered in radians.
M, left parenthesis, t, right parenthesis, equals, 21, cosine, left parenthesis, start fraction, 2, pi, divided by, 687, end fraction, t, right parenthesis, plus, 228
How many days later does Mars first reach 220 million start text, k, m, end text from the Sun?
Round your final answer to the nearest whole day.
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text