1. ## Graphs & Degrees

I'm trying to translate the slope into degrees.

I know the formula for slope (y2-y1)/(x2-x1) = slope

The difficultly is now translating that into degrees.

I saw a formula that suggested it could translate it, but in practice I've found either it doesn't or I'm using it all wrong.

(slope * 180)/(pi) = degrees

So as an example of how it's not working; slope is 40/2 = 20.

(20 * 180)/(pi) = degrees
(3600)/(3.14) = degrees
1146 = degrees

I know I've got something incorrect here, but I don't know what it is.

Any input is greatly appreciated!

2. ## Re: Graphs & Degrees

Originally Posted by Phoenix999
I'm trying to translate the slope into degrees.
I know the formula for slope (y2-y1)/(x2-x1) = slope
The difficultly is now translating that into degrees.
I saw a formula that suggested it could translate it, but in practice I've found either it doesn't or I'm using it all wrong.
(slope * 180)/(pi) = degrees
So as an example of how it's not working; slope is 40/2 = 20.
(20 * 180)/(pi) = degrees
(3600)/(3.14) = degrees
1146 = degrees
I know I've got something incorrect here, but I don't know what it is.
I am sorry to tell you this, but your posting makes very little sense whatsoever.

Slope is the tangent of the angle that a line makes with the x-axis in the positive direction.
So suppose the line has slope $\displaystyle m$.
If $\displaystyle m\ge 0$ then that angle is $\displaystyle \theta=\arctan(m)$

If $\displaystyle m< 0$ then that angle is $\displaystyle \theta=\pi+\arctan(m)$

Now in either case a mathematical cave man(i.e. someone who still uses degrees) can use that conversion formula.

3. ## Re: Graphs & Degrees

Thank you for responding. I truly appreciate any help you can give. There is no reason to be sorry. If I knew what I was doing, then I wouldn't be here.

I have a photo. It is 4000 by 4000 pixels. I use a program (GIMP) to draw a random line x1 y1 to x2 y2. I am able to then ask the program for the specific x & y coordinates. I'm trying to use those coordinates to help adjust the brush's angle to match the line's (for lack of a better word) angle on the photo. I assumed using a slope equation would be the best method.

I'm hoping you could clarify some items for me.

First, I do not know what (-) stands for.
Second, can you translate arctan into caveman
And lastly, is arctan(m) = arctan * (m)

If this is the wrong area to make this post, I hope I'm not offending anyone with my simplistic inquiry. I thought this was the basic math area. If it's not, maybe someone can direct me to proper place.

Thank you and all input is appreciated.

4. ## Re: Graphs & Degrees

Originally Posted by Phoenix999
Thank you for responding. I truly appreciate any help you can give. There is no reason to be sorry. If I knew what I was doing, then I wouldn't be here.

I have a photo. It is 4000 by 4000 pixels. I use a program (GIMP) to draw a random line x1 y1 to x2 y2. I am able to then ask the program for the specific x & y coordinates. I'm trying to use those coordinates to help adjust the brush's angle to match the line's (for lack of a better word) angle on the photo. I assumed using a slope equation would be the best method.

I'm hoping you could clarify some items for me.

First, I do not know what (-) stands for.
Second, can you translate arctan into caveman
And lastly, is arctan(m) = arctan * (m)

If this is the wrong area to make this post, I hope I'm not offending anyone with my simplistic inquiry. I thought this was the basic math area. If it's not, maybe someone can direct me to proper place.

Thank you and all input is appreciated.
This a mathematics help forum. As such we help people who study mathematics with their questions.
This is not a forum for those of limited knowledge.

5. ## Re: Graphs & Degrees

I am studying mathematics. I just have not reached this level yet. Ironically enough, I am trying to expand my knowledge. I did Google arctan and I assure you It did not produce anything that I could simply relate to your post. Try Googling (-). And the arctan(m), I'm fairly certain it is meant to be multiplied. I was simply asking for a clarification. I was polite in my first post and my second. What happened here is plainly silly.

6. ## Re: Graphs & Degrees

Just as an addition, I've learned that within GIMP Script-fu, I can only use atan within my calculations. How would I convert:

If m>0 then that angle is (-) = arctan(m)

If m<0 then that angle is (-) = pi + arctan(m)

Thanks.