题目

John and Bobby joined the same company together just after they completed their university studies the same year. Both of them worked very hard. Several years later, however, the boss promoted(提拔) Bobby to manager but John was still a worker. John could not take it, and gave his resignation（辞职书） to the boss. He complained that the boss did not think much of those who were hard -working, but promoted only those who flattered him. The boss knew that John had worked very hard for the years. He thought a moment and said, “Thank you for what you said, but I hope you will do o 设函数，满足，则的值是__________。