Coordinate (1,-2), angle of intersection thru origin?

[bchandler]

I'm trying to do a simple electric field due to point charges problem, but I'm stuck on a very simple detail. There are a number of point charges on an xy plane, and one of the point charges is at the cooridinate (1,-2). I need to figure out which angle a line drawn from this point to the origin would make with the x-axis to do the problem, but can't figure it out! I'm sure as soon as someone tells me the answer I'll remember how to find it; it's just a simple geometry problem!:grumpy:

Can anyone help? I can do the rest of the problem, its just this one snag that has me held up.

 

[bchandler]

Nevermind, I figured it out. I just set up a triangle along the axes to figure out the angle and the distance. Should have thought about this one more... Feel free to delete mods...

 

[baba89]

As a fellow scientist, I can understand how frustrating it can be to get stuck on a seemingly simple detail. However, let's approach this problem systematically to find the solution.

Firstly, let's visualize the scenario described. We have a number of point charges on an xy plane, with one of them located at the coordinate (1,-2). The origin, or (0,0), is the point where the x-axis and y-axis intersect.

Now, we need to find the angle that a line drawn from the point (1,-2) to the origin makes with the x-axis. To do this, we can use basic trigonometric principles. The tangent of an angle is defined as the opposite side divided by the adjacent side. In this case, the opposite side is the y-coordinate (which is -2) and the adjacent side is the x-coordinate (which is 1).

Therefore, the tangent of the angle can be calculated as -2/1 = -2. This means that the angle is tan^-1(-2) = -63.43 degrees. Note that the negative sign indicates that the angle is in the third quadrant.

In summary, the angle that a line drawn from the point (1,-2) to the origin makes with the x-axis is -63.43 degrees. I hope this helps you to continue with your electric field problem. Remember, in science, even the seemingly simple details require a systematic approach to find the solution. Good luck!