Why I Get X & Y Mixed Up When Plotting Graphs

In summary, when Plotting a graph, if you want to plot x=3, y=2, you need to put the 3 in the x-axis.
  • #1
Ziggletooth
5
0
Ok so I don't know what is wrong with me, but when it comes to graphs I often get x and y mixed up and the whole thing becomes very confusing.

I had this question

plot a graph using y = 2/3x

The answer is:

if x = 3
y = (2/3 * 3) = 2
x = 3, y = 2

and these are integers which can be plotted very easily on the graph.

I got confused and did this

y = 2/3x
(y * 3) = (2/3x * 3)
3y = 2x
(3y / 2) = (2x / 2)
x = 1.5y

Obviously this is very wrong (if x = 3, y = 4.5 which is != 2 as above), but I'm not sure why. This is an equation isn't it? and those are the sort of balancing things you do to solve equations, so why has it gone so horribly wrong?
 
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  • #2
Ziggletooth said:
Ok so I don't know what is wrong with me, but when it comes to graphs I often get x and y mixed up and the whole thing becomes very confusing.

I had this question

plot a graph using y = 2/3x

The answer is:

if x = 3
y = (2/3 * 3) = 2
x = 3, y = 2

and these are integers which can be plotted very easily on the graph.

I got confused and did this

y = 2/3x
(y * 3) = (2/3x * 3)
3y = 2x
(3y / 2) = (2x / 2)
x = 1.5y

Obviously this is very wrong (if x = 3, y = 4.5 which is != 2 as above), but I'm not sure why. This is an equation isn't it? and those are the sort of balancing things you do to solve equations, so why has it gone so horribly wrong?

When you want to plot the graph of a line $y=ax$, you pick a value of $x$ that you want, say $x_1$, and you find the corresponding $y$, say $y_1=ax_1$ and since $(0,0)$ satisfies the equation of the line, you draw a line that passes through $(0,0)$ and $(x_1,y_1)$.
 
  • #3
evinda said:
When you want to plot the graph of a line $y=ax$, you pick a value of $x$ that you want, say $x_1$, and you find the corresponding $y$, say $y_1=ax_1$ and since $(0,0)$ satisfies the equation of the line, you draw a line that passes through $(0,0)$ and $(x_1,y_1)$.

I'm sorry, I don't think I was clear. I understand that much but I want to know what was wrong with my method, did I do an operation wrong or can you not do it that way, and if so why not? Because it looks like an equation to me and that's how one would usually simplify an equation.

I don't wish to barrage this forum but in addition to that I do have another question. I said at the beginning I seem to get the coordinates x and y mixed up all the time and I can't reliably tell which is which. Here are two questions and both times I got the coordinates mixed up perhaps you can help me understand which is which.

So the first question is to plot

y = 1 2/3x

I do this
y = 5/3x
3y = 5x

and then I plot the coordinates 5,3 because I read it as 'for every 3y there is 5x' I go up 3 places on the y-axis and then along 5 places on the x axis.

The correct answer is 3,5

My brain doesn't seem to jump to this conclusion, so I figure I'll remember that (a * y = b * x) = (a * x = b * y ) that is to say, switch the coefficients because it seems like that works for some reason.

Anyway the next question

Graph the line that represents a proportional relationship between d and t with the property that an increase of 5 units in t corresponds to an increase of 2 units in d.

What is the unit rate of change of d with respect to t? (That is, a change of 1 unit in t will correspond to a change of how many units in d?)

I figure it's 5t = 2d so d = 2/5

Now I go to graph it, but I remember the rule I came up with about switching the coefficients, so I move 2 places on the t axis and 5 places on the d axis... and what a surprise, I got it wrong again it's the other way. I just can't seem to win here.

Can someone help me clear the mist surrounding this concept so I can place the coordinates correctly.
 
  • #4
Ziggletooth said:
y = 2/3x
(y * 3) = (2/3x * 3)
3y = 2x
(3y / 2) = (2x / 2)
x = 1.5y

Obviously this is very wrong (if x = 3, y = 4.5 which is != 2 as above), but I'm not sure why. This is an equation isn't it? and those are the sort of balancing things you do to solve equations, so why has it gone so horribly wrong?

When you say \(\displaystyle x=3\), that means you put the 3 where the \(\displaystyle x\) is!

\(\displaystyle 3=1.5y\).

Now try it.
 

Related to Why I Get X & Y Mixed Up When Plotting Graphs

1. Why do I often mix up X and Y when plotting graphs?

This is a common mistake, especially for those who are new to graphing. One possible reason is that the X and Y axes are often labeled differently depending on the type of graph. For example, in a line graph, the X-axis may represent time while the Y-axis represents the variable being measured. This can cause confusion when switching between different types of graphs.

2. Does this mistake affect the accuracy of my graph?

In most cases, mixing up X and Y will not affect the accuracy of your graph. However, if you are plotting data that has a strong correlation between X and Y, such as in a scatter plot, the mistake can lead to incorrect interpretations of the data. It is important to double check your axes labels to avoid any misinterpretations.

3. How can I prevent mixing up X and Y when plotting graphs?

One way to prevent this mistake is to always label your axes clearly and consistently. If you are using a software program, make sure to double check the labels before finalizing your graph. Additionally, it can be helpful to mentally remind yourself which axis represents which variable before starting to plot your data.

4. Are there any tips for remembering which axis is X and which is Y?

One helpful tip is to remember that the X-axis is typically the horizontal axis and the Y-axis is the vertical axis. Another tip is to think about the order of the letters in the alphabet - X comes before Y, so it is usually plotted on the left side of the graph.

5. Is there a scientific explanation for why I mix up X and Y when plotting graphs?

While there is no specific scientific explanation, it is believed that the human brain tends to naturally read from left to right. This can cause us to unconsciously focus more on the X-axis, leading to a mix up with the Y-axis. With practice and careful attention, this mistake can be minimized or avoided altogether.

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