Determine the angle between a vector and the x or y axis.

[fossil gazelle]

I dont get where the angle is, or what part I calculate.

[sonic sparrow]

it would be arctan(y/x)

I believe

[fossil gazelle]

whats arctan?

[sonic sparrow]

tan^-1

[fossil gazelle]

ohh just that?

[fossil gazelle]

so what if it said clockwise

[sonic sparrow]

it just wouldn't be

[wanton sparrow]

draw a picture

[fossil gazelle]

I do but, phrases like 'from the positive x -axis' i dont get.

[sonic sparrow]

so it starts in the positive x axis

and goes anticlockwise around the centre pivot point

at some angle θ

[sonic sparrow]

like that

[wanton sparrow]

woah

-1 🤔

[fossil gazelle]

ohhhhh

this makes a lot of sense.

Thank youu

[wanton sparrow]

also for your original question

you would have to do 180 - arctan(y/x)

[fossil gazelle]

wait so does this include the angle in the triangle?

[wanton sparrow]

no

it's the angle the VECTOR makes with the x axis

[fossil gazelle]

so 180 - tan^-1(y/x)

[wanton sparrow]

the angle in the triangle is what arctan(y/x) will give you

[fossil gazelle]

ohh

[wanton sparrow]

yeh but make sure y>0 and x>0

[fossil gazelle]

so instead of -1 i should make it 1

[wanton sparrow]

yes

because you are thinking about "lengths" in trig and you cannot have a negative length