Domain & Range
Domain and Range
Range
To find the range, you must find the minimum or maximum value of the function, which is going to be the vertex. If the maximum value of the function is (3, 17), then the output cannot be greater than 17. The range is all values of y such that y is less than or equal to 17, or in set notation: 
. If there is a minimum value at (1, 4), then the output cannot be less than 4. The range is all values of y such that y is greater than or equal to 4, or in set notation: 
.
. If there is a minimum value at (1, 4), then the output cannot be less than 4. The range is all values of y such that y is greater than or equal to 4, or in set notation: . In general, if the parabola opens upward, the range of the quadratic function
f(x) = ax2 + bx + c is, 
. If the parabola opens downward, the range of the quadratic function f(x) is, 
.