Constant establishment of inequality in senior one

When they are both quadratic functions (that is, A is not equal to zero)

1. the identity should be that the opening is upward and does not intersect with the y axis, that is, A >；; 0，△& lt； 0

An empty set should be opened downward and have at most one intersection with the Y axis, namely A.

2. The invariance should be that the opening is downward and there is no intersection with the Y axis, that is, A.

An empty set should have an upward opening and at most one intersection with the Y axis, that is, A >；; 0，△& lt； =0

3. The invariance should be that > the opening is upward and there is at most one intersection point with the Y axis, that is, a >；; 0，△& lt； =0

The empty set should be open upward and have no intersection with the Y axis, that is, A.

4. Consistency should be that < opening is downward, and there is at most one intersection point with Y axis, that is, A.

The empty set should be open upward and not intersect with the y axis, that is, A >；; 0，△& lt； 0