特殊数学符号e、π等的计算

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e

def calc_e(bais=0.000001):
    ret = 1
    jie_cheng = 1
    i = 1

    while True:
        last_term = 1.0/jie_cheng
        if last_term >= bais:
            ret += last_term
            i += 1
            jie_cheng *= i
        else:
            return ret

    return ret


def main():
    ret = calc_e()
    print(ret)


if __name__ == '__main__':
    main()

π

def calc_pai(bais=0.00001):
    ret = 0
    sign = 1
    odd_num = 1

    while True:
        last_term = 1.0/odd_num

        if last_term >= bais:
            ret += last_term*sign
            odd_num += 2
            sign = -sign
        else:
            return ret*4


def main():
    ret = calc_pai()
    print(ret)


if __name__ == '__main__':
    main()