Question

Which is the angle of this line? P1(-1,0) P2(0,-sqrt3)

So the slope is -sqrt 3...

Answer 1

(It asks the angle related to the positive part of x

Answer 2

Tan -1 of sqrt of 3 is -60...should I add that to 180? or to 90? or what am I supposed to do?

Answer 3

hmm are you doing vectors?

Answer 4

Yep

Answer 5

\(\bf \textit{angle between two vectors }\\ \quad \\
cos(\theta)=\cfrac{u \cdot v}{||u||\ ||v||} \implies \cfrac{\text{dot product}}{\text{product of magnitudes}}\\ \quad \\
\theta = cos^{-1}\left(\cfrac{u \cdot v}{||u||\ ||v||}\right)\)

Answer 6

Oh...but this is just a line and it asks the angle with the x axis

Answer 7

It gives me two points of the lines...vectors are not necesary for this, I think

Answer 8

well... haemm I'd think is 2 vectors in standard position, that is, their starting point is the origin

Answer 9

though if you draw them, the angle is very visible, since notice the 0's
one is a moving over one axis, the other over the other axis

Answer 10

But what do I need to do, then? :( I got this formula :
Angle = tan-1 of sthe slope

So that is -60, but this is part two of the graph, so I don't know what should I do now

Answer 11

Oh...I would add 90 to the 60...and 150 could do it