what quadrant is cos-120 in?

[spoog74]

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hi, just to make sure im not going crazy can anyone tell me what quadrant cos(-120) is in and why?

 

[qnzbabi91]

hi, just to make sure im not going crazy can anyone tell me what quadrant cos(-120) is in and why?

Third bc you go counterclockwise on cartesian plane 360-120 =240 degrees clockwise or in other words the third quadrant.

 

[magriva]

Cos:

I quadrant: +
II...........: -
III: -
Iv: +

120 is in the ii quadrant

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[spoog74]

Cos:

I quadrant: +
II...........: -
III: -
Iv: +

120 is in the ii quadrant

Sent from my SGH-T999 using SDN Mobile

i thought this too but your'e wrong. Its in the third quadrant.

 

[PointEstimate]

Cos:

I quadrant: +
II...........: -
III: -
Iv: +

120 is in the ii quadrant

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This will tell you whether the cosine of that number is positive or negative. You need to do what qnzbabi91 suggested to find out which quadrant cos(-120) is in.

 

[awaitsimpatient]

Learn CAST
C for quadrant IV,
A for quadrant I,
S for quadrant II,
T for quadrant III
quadrant I is A meaning "All" are positive
Quadrant II is S meaning only "sin" is positive
Quadrant III is T meaning only "tan" is positive
Quadrant IV is C meaning "cos" is positive


S A
T C

A = All Functions +
S = Sine only+
T = Tangent only+
C = Cosine only+

If you do not apply laws end up 120 on quadrant II but then you take the inverse to give you quadrant III, I think, equivalent to 240 degrees
** but yea, not 100% sure coming from a person that got 13QR lol

 

[FeralisExtremum]

What it asks for the sin/cos/etc of a positive value, you move counter clockwise starting from the x axis of the first quadrant. If it asks about a negative degree value, you instead move clockwise from that same starting point.