question about angle of inclination (1 Viewer)

[jjuunnee]

Let's say we have to find the angle of inclination of a line with equation 2x + 3y + 11 = 0

so m = -2/3 and therefore tanx = -2/3

but that gives us the answer x= -34, and this negative angle really bugs me because I don't know what to do with it. Most of the time I just ignore the negative and go on to find the angle (180-34 = 146) and it's still the correct answer but I feel like I'm not working it out correctly.

I don't know. I'm just really confused. Explanations??

 

[InteGrand]

Let's say we have to find the angle of inclination of a line with equation 2x + 3y + 11 = 0

so m = -2/3 and therefore tanx = -2/3

but that gives us the answer x= -34, and this negative angle really bugs me because I don't know what to do with it. Most of the time I just ignore the negative and go on to find the angle (180-34 = 146) and it's still the correct answer but I feel like I'm not working it out correctly.

I don't know. I'm just really confused. Explanations??

The significance of the negative sign is that the line makes an angle of 34 degrees below the horizontal (because it's sloping downwards).

 

[jjuunnee]

The significance of the negative sign is that the line makes an angle of 34 degrees below the horizontal (because it's sloping downwards).

Ah that makes sense, but is my method of working out still correct?

 

[InteGrand]

Ah that makes sense, but is my method of working out still correct?