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

[ 1/1Inequality]
    Assignment:Find the solution set of inequality (1/n)*cos(nπ/2) <0.1 .
    Question type: Inequality
    Solution:
    The inequality can be reduced to 1 inequality：
         ( 1 / n ) * cos ( n * π / 2 ) <0.1         (1)
        From the definition field of divisor
        x ≠ 0        (2 )

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    From inequality(1)：
         n < -√688682759/√7000000 或  -√688682759/√7000000 < n < -6.545699 或  -√1005589/√35000 < n < -2.818129 或  -1.068129 < n < 0 或  0.940065 < n < 3.207897 或  4.689281 < n < 7.54416
    From inequality(2)：
         n < 0 或  n ＞ 0

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    From inequalities (1) and (2)
         n < -√688682759/√7000000 或  -√688682759/√7000000 < n < -6.545699 或  -√1005589/√35000 < n < -2.818129 或  -1.068129 < n < 0 或  0.940065 < n < 3.207897 或  4.689281 < n < 7.54416     (3)

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    The final solution set is :
         n < -√688682759/√7000000 或  -√688682759/√7000000 < n < -6.545699 或  -√1005589/√35000 < n < -2.818129 或  -1.068129 < n < 0 或  0.940065 < n < 3.207897 或  4.689281 < n < 7.54416

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