COORDINATE GEOMETRY
71 . Domain and Range of a Function
The domain of a function is the set of values for which the function is
defined. For example, the domain of is all values of x except 1
and −1, because for those values the denominator has a value of 0 and the
fraction is therefore undefined. The range of a function is the set of outputs
or results of the function. For example, the range of f(x) = x^2 is all numbers
greater than or equal to zero, because x^2 cannot be negative.
72 . Finding the Distance Between Two Points
To find the distance between points, use the Pythagorean theorem or
special right triangles. The difference between the x’s is one leg and the
difference between the y’s is the other.
In the figure above, PQ is the hypotenuse of a 3-4-5 triangle, so PQ = 5.
You can also use the distance formula:
