Why doesn't Desmos show the X-intercept for non-linear equations?

  • Thread starter CallMeDirac
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In summary, the conversation discusses the use of desmos to graph lines and equations, specifically focusing on the display of intercepts. It is noted that while equations such as sin(x) show intercepts, more complicated equations like sin(50)=5/x do not always show the intercepts. The expert suggests that this is because plotting a function and solving a linear equation are not the same operation, and that zooming out the graph can reveal the intercepts for equations like sin(50)=5/x. The conversation concludes with a clarification on the use of desmos and a response to a skeptical reaction.
  • #1
CallMeDirac
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Often in desmos when you graph a line it shows the X and Y-intercept with a grey dot.
However when I graph something like sin(50)=5/x it doesn't show
which I find odd because sin(x) does show the intercepts

It only gets more complicated when graphing tangent and cosine. Both DO show the X-intercept. Further Cotangent and Secosine also do show the intercept.

why
 
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  • #2
I don't know desmos, but what do you expect when plotting "something like sin(50)=5/x "?
Hint1: sin(x) is a function, your other expression is an equation
Hint2: sin(50) is a constant, 5 is a constant, so what is the solution of your equation?
 
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  • #3
I was wrong

Turns out its not the function (sine tan etc.)
it's where the x is

if the x is the numerator ( sin(60)=x/30) it will show the dot
but if it is the denominator (sin(60)=30/x) it wont

still why
 
  • #4
lomidrevo said:
I don't know desmos, but what do you expect when plotting "something like sin(50)=5/x "?
Hint1: sin(x) is a function, your other expression is an equation
Hint2: sin(50) is a constant, 5 is a constant, so what is the solution of your equation?

I was just talking about intercepts
it only shows the x-intercept when the x is in the numerator (see previous post)

edit: desmos will show the x-intercept for equations (65+x=180 will show an intercept at 115)
 
  • #5
It shows, you just need to zoom out the graph. If you solved your equations, you would see that solution for ##x## are located out of the range of the default zoom (in my browser it is from -10 to 10).

As I told you in my previous post, plotting a function (like ##y=f(x)##) and solving a linear equation with one unknown are not the same operation. It is a feature of this tool, that it gives you the solution graphically. That is a vertical line for constant ##x##. However, I am not sure what is skeptical about my post according to you. Both provided hints would lead you to discover answer to your question.
 
  • #6
lomidrevo said:
It shows, you just need to zoom out the graph. If you solved your equations, you would see that solution for ##x## are located out of the range of the default zoom (in my browser it is from -10 to 10).

That's irrelevant
 
  • #7
lomidrevo said:
As I told you in my previous post, plotting a function (like ##y=f(x)##) and solving a linear equation with one unknown are not the same operation. It is a feature of this tool, that it gives you the solution graphically. That is a vertical line for constant ##x##.

that would make sense if the x intercept was also not present in the equation with the numerator.

lomidrevo said:
However, I am not sure what is skeptical about my post according to you. Both provided hints would lead you to discover answer to your question.

You didn't, that's why I used a skeptical reaction. I explained in a previous post that it plots similar equations, furthermore the question was about a grey point showing the x-intercept not the lack of a representative line.
 

1. Why doesn't Desmos show the X-intercept for non-linear equations?

Desmos does not show the X-intercept for non-linear equations because the X-intercept only exists for linear equations, where the graph crosses the X-axis at a single point. Non-linear equations, on the other hand, have curves or multiple branches, making it impossible to pinpoint a single X-intercept.

2. Can I still find the X-intercept for a non-linear equation on Desmos?

Yes, you can still find the X-intercept for a non-linear equation on Desmos by using the "Intersect" tool. First, graph the non-linear equation and then graph a linear equation that crosses the X-axis at the desired X-intercept. The point of intersection between the two graphs will be the X-intercept for the non-linear equation.

3. Is there a way to see all the X-intercepts for a non-linear equation on Desmos?

No, there is no way to see all the X-intercepts for a non-linear equation on Desmos. Since non-linear equations have curves or multiple branches, there can be an infinite number of X-intercepts, making it impossible to display them all on a graph.

4. Why does Desmos only show the X-intercept for linear equations in the table of values?

Desmos only shows the X-intercept for linear equations in the table of values because it is the only equation where the X-intercept exists as a single point. Non-linear equations have curves or multiple branches, so the X-intercept cannot be represented as a single value in the table of values.

5. Can I change the settings on Desmos to show the X-intercept for non-linear equations?

No, you cannot change the settings on Desmos to show the X-intercept for non-linear equations. This is because the X-intercept only exists for linear equations, and changing the settings will not alter the fundamental properties of non-linear equations.

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