Overview: 1 questions will be solved this time.Among them
           ☆1 inequalities

[ 1/1Inequality]
    Assignment:Find the solution set of inequality cos(π*(t-8)/2) <= -0.5 .
    Question type: Inequality
    Solution:
    The inequality can be reduced to 1 inequality：
         cos ( π * ( t - 8 ) / 2 ) <= -0.5         (1)

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    From inequality(1)：
         t ≤ -28/3 或  -20/3 ≤ t ≤ -16/3 或  -8/3 ≤ t ≤ -4/3 或  4/3 ≤ t ≤ 8/3 或  16/3 ≤ t ≤ 20/3 或  t ≥ 28/3

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    The final solution set is :
         t ≤ -28/3 或  -20/3 ≤ t ≤ -16/3 或  -8/3 ≤ t ≤ -4/3 或  4/3 ≤ t ≤ 8/3 或  16/3 ≤ t ≤ 20/3 或  t ≥ 28/3
    *Note: Radian.

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