Thread: The Graphs of Function and Relation

Graph each equation and identify if it's a mere relation or function by vertical line test.

1.) |y|=x
2.) y= x raise to the 3rdpower + 1
3.) 2y = ( -2x+3 )


I DON'T know how to answer help pls.

Originally Posted by ejaykasai

Graph each equation and identify if it's a mere relation or function by vertical line test.

1.) |y|=x
2.) y= x raise to the 3rdpower + 1
3.) 2y = ( -2x+3 )


I DON'T know how to answer help pls.

Dear ejaykasai,

Let me give you some hints;

For the first one use the definition of the absolute value function.



For the second equation use the fist and second derivatives to sketch the graph. If you do not know how to do this please refer Graphing Using First and Second Derivatives

The third one can be rearranged as, So this is a equation of a straight line.

Hope you can continue.

Originally Posted by Sudharaka

Dear ejaykasai,

Let me give you some hints;

For the first one use the definition of the absolute value function.



For the second equation use the fist and second derivatives to sketch the graph. If you do not know how to do this please refer Graphing Using First and Second Derivatives

The third one can be rearranged as, So this is a equation of a straight line.

Hope you can continue.

My problem is that I don't know how to remove the absolute value of y? " | y | "

What I would simply do is, since I know how to draw the graph of , draw it and rotate the whole graph 90 degrees so that y and x axis swap there places

Originally Posted by ejaykasai

My problem is that I don't know how to remove the absolute value of y? " | y | "

That is exactly what you could do with the definition of the absolute value function.





Therefore, ----------(1)

-------(2)

Combining (1) and (2) we can write;



Hope you can sketch the graph now.

Originally Posted by BAdhi

What I would simply do is, since I know how to draw the graph of , draw it and rotate the whole graph 90 degrees so that y and x axis swap there places

Technically, the operation you need to do is reflect the graph about the line y = x. That happens to do the same thing in this case, but in general, the rotation is incorrect. Any time you swap the roles of x and y, you are graphically reflecting about the line y = x.

Is this right?
instead of assigning first values of x, values of y 1st, then solve for x:

Example:

when y = 0, x = 0 (0, 0)
when y = 1, x = 1 (1, 1)
when y = -1, x = 1 (1, -1)
when y = 2, x = 2 (2, 2)
when y = -2, x = 2 (2, -2)

when I solved the |y| = x using the default values, the graph goes like this-->
|y|=x | Flickr - Photo Sharing! ?? Is this correct?

Is this right?
instead of assigning first values of x, values of y 1st, then solve for x:

Example:

when y = 0, x = 0 (0, 0)
when y = 1, x = 1 (1, 1)
when y = -1, x = 1 (1, -1)
when y = 2, x = 2 (2, 2)
when y = -2, x = 2 (2, -2)

when I solved the |y| = x using the default values, the graph goes like this-->
|y|=x | Flickr - Photo Sharing! ?? Is this correct?

No your graph is incorrect. Please check whether the highlighted values are marked in the graph correctly.