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

[ 1/1Inequality]
    Assignment:Find the solution set of inequality 40tana-19.62/（cosa）^2 >= 13 .
    Question type: Inequality
    Solution:
    The inequality can be reduced to 1 inequality：
        40 * tan a - 19.62 / ( cos a ) ^ 2 >= 13         (1)
        From the definition field of divisor
         cos x ≠ 0        (2 )

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    From inequality(1)：
        The solution set is empty, that is, within the range of real numbers, the inequality will never be established!
    From inequality(2)：
         a < -14.137167 或  -14.137167 < a < -10.995574 或  -10.995574 < a < -7.853982 或  -7.853982 < a < -4.712389 或  -4.712389 < a < -1.570796 或  -1.570796 < a < 1.570796 或  1.570796 < a < 4.712389 或  4.712389 < a < 7.853982 或  7.853982 < a < 10.995574 或  10.995574 < a < 14.137167 或  a ＞ 14.137167

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    The final solution set is :
        The solution set is empty,that is, the inequality will never be estatlished within the real number range.

    *Note: Radian.

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