What do they mean by that??

[frail kindle]

alpha is the angle

the rules for sin are
sin is positive inthe first and second quadrant
sin is negative in the 3rd and 4th quadrant

this means if the value for α = sin^-1(x) is negative you do 180 - α or 360 + α

[chrome skiff]

Where do quadrants come from in sin? Is it the angle

?

[frail kindle]

so

0 - 360 is 4 quadrants

each quadrant is 90 degrees

[chrome skiff]

Ok

It is a bit weird

Just draw the sin graph

Lol

[frail kindle]

yeah true

but i find this quicker

cuz i memorised all the rules

(also i suck at drawing)

[chrome skiff]

This is maths exam

[frail kindle]

use this

for reference

the equations such as 180 - x or 360 - x are to find positive values for the trigonometric ratio between 0 < x < 360

[untold anchor]

i dont get the quadrant stuffff

and i have not memorised the graphs either

[frail kindle]

its a bit confusing

but each quadrant on a trig graph is 0-90 degrees

[untold anchor]

ive just memorised the thingies like costheta=cos(360+-theta) and that stuff

[frail kindle]

yeah same

[left hound]

there is an easier way of doing it

i dont use the cast diagram

[frail kindle]

Np

[hasty egret]

dont use CAST its a headache