Functions have graphs that pass the Vertical Line Test: no vertical line will cross the graph more than once.
So do the graphs and look at the results.
Well today I received this question in class:
Identify each type of relation and predict whether it is a function. Then graph each function and use the vertical-line test to determine whether your prediction was correct.
a) y = 5 - 2x
b) y = 2x squared - 3
c) y = y = -3/4 (x + 3) squared + 1
d) x squared + y squared = 25
My question is, how will I know what type of function it is by just looking at the relations, and how would I imagine how each graph of one would look like? (Is there a rule I have to memorize?)
GR.11 Math (I forgot my GR.10 )
Welcome to Math Help Forum!
For instance, you may know that:
- is a relation that produces a straight-line graph
- produces a symmetrical curve - in fact, a parabola - with a vertical axis of symmetry
- describes a circle centre the origin radius , since is the square of the distance of the point from the origin.
You should now be able to make predictions about all four of the examples you've been given.