Mathematics of the college entrance examination: when the second question of the derivative problem is to find the interval, the constant A is always assigned to the field and discussed in different categories. What is the basis of homework discussion? thank you If the derivative is a linear function, discuss whether its zero point is within the range of the original function, and if not, it is on the left or right.

If the derivative is a quadratic function, then in addition to the discussion of the zero point above, it is necessary to discuss the symmetry axis, and the discussion content is consistent with the above.