Maths methods help-Functions

[danfer073]

I would like help with questions 2aceg the question is Sketch the graph of each of the following relations then state the range of each and specify whether the relation is a function or not

[zhen]

First, to tell whether or not something is a function u use the vertical ine test. So u draw a vertical line and to be a function it can only touch one point in the graph. This has to work no matter where u do the vertical line test. Another way to think about it is that in a function for every x value there is only one y value. So, a circle is not a function since for every x value there are 2 y values. Whereas, a linear graph is a function since for every x value there is only one y value. In the attatchment i have put a circle and a verticle line. See how the vertical line cuts the circle twice. That means it isn't a function. Also to find the range, you have to find the y values which the relation exists. For 2a for example the lowest value of y occurs when x=0, since (0,0) is the turning point. So and the highest value occurs when x=4. The domain is from 0 to 4 and obviously 4^2 is greater than 3^2 or any number between 0 and 4 squared. So if u sub in these values u get [0,16] as the range. Sorry this was a bit wordy, tell me if you didn't understand my explanation.