Problem with solving a maths task in excel.

[jozeke]

Hello everyone!

I've recently got a task to do in excel:

"There are points A(-1,0) and B(3,0). Find point C, for which the ACB angle is a right angle."

There was also something mentioned about the method of searching an axis???

I understand this and I know how do do it on paper but have absolutely no clue how to transfer it to excel. I think I should use a formula that points out the point C coordinates just by typing in the coordinates of points A and B. Does anyone know a formula like that or how to use a couple of them in order to get the result?

Regards

 

[Joe4]

Welcome to the Board!

This looks like a homework problem or school assignment of some type. Note that I don't think you will find anyone here who wants to do your assignment for you.
However, we may be able to give you some tips to point you in the right direction.

If you explain here how you would do this on paper, we may be able to provide some hints on how to do the same thing in Excel.

 

[jozeke]

Hi!
Yes, it is a homework but it caused a big trouble in class as nobody could solve it (nor the teacher probably) so after two weeks of struggling with it I decided to post it on a forum. I thought it's possible to just write one long formula and solve it but as I see it is not. So I solved it more "manually" and just typed a single formula for every variable and made a drawing of that, so I already did that.

But if you want to know how to do it on paper, it's simply using pythagorean theorem and counting the variables one by one using equations and systems of equations. This is not a really difficult task and the final answer is square root of 3. In Excel I wrote all the equations next to the actual formulas to make the teacher understand how I know the variables' values.

So I think we can consider this topic as closed as I've done the task and I don't need anything more.

Regards

 

[Joe4]

Interesting.

This is not a really difficult task and the final answer is square root of 3.

I thought you were looking for a coordinate, not a single value though.

"There are points A(-1,0) and B(3,0). Find point C, for which the ACB angle is a right angle."

And couldn't there be more than one point that satisfies your requirement?

 

[jozeke]

Well, I did not say at any stage that this task is difficult in terms of maths, my only problem was putting that to excel. And yes, there are two points that match my requirements and their coordinates are (0,√3) and (0,-√3) (I didn't write this point needs to be on the y axis, I missed it while translating the task). So my answer (√3) is the distance between the point (0,0) and the point C).

 

[pgc01]

Hi

Maybe I'm not understanding the problem correctly, but it seems a very simple problem, that your teacher would solve in 1 minute.
I don't see why you say your teacher would not be able to do it.

If I remember correctly from high school (some dozens of years ago) if you consider A and B the diameter of a circle, any point C different from A and B on the edge of that circle will satisfy your ACB being a right angle.

This means there are an infinity of solutions, the points

(x-1)^2+y^2=4

If you say the point is in the Y axis then x=0, which means y=+/-√3