# Quadrants and "CAST" Rule

• May 31st 2008, 05:58 AM
PlatinumChris
Quadrants and "CAST" Rule
I'm having some problems with the CAST rule and the 4 quadrants.

i think i have the basics worked out.

the thing i don't know how to do is answers questions such as:

SinX-1 = 30, for example.

could anyone help me to understand this?
• May 31st 2008, 07:00 AM
TheEmptySet
Quote:

Originally Posted by PlatinumChris
I'm having some problems with the CAST rule and the 4 quadrants.

i think i have the basics worked out.

the thing i don't know how to do is answers questions such as:

SinX-1 = 30, for example.

could anyone help me to understand this?

I think we have a problem here. I think that this is the equation you mean

$\sin(x-1)=30$ if it is this has No REAL solutions(It does have complex solutions). If you think about it the sine function described above has an amplitude of 1 so its max value will be one. So there is no way that it can ever reach 30.

As far as the CAST rule it tells us what trig functions are positive and where.
It starts in quadrant three where C=cosine is positive. Moving counter clockwise to quadrant one A= All are positive. Next to quadrant two S=sine is positive. Finally, to quadrant three where tangent is positive.

I hope this helps.