The answer can be obtained by observing the trend of numerical changes in the table; Using the conclusion of odd function's symmetry sum; Using derivative to study monotonicity of function, we can get extreme value. Solution: Observe the trend of the value changing with the value in the table. When it is known, there is a minimum value of: According to odd function's symmetry, the function has a maximum value in the interval. At this time, the range of the function in the interval is that there is neither a maximum nor a minimum in the interval. At this time, it is solved. At that time, the function monotonously decreased in this interval; At that time, the function monotonically increased in this interval. The function gets the minimum value, that is, the minimum value. Learning to observe and analyze, mastering the symmetry of odd function and studying the monotonicity extreme value of the function by using derivatives are the keys to solve the problem.