+8 In this problem: sin 240 x sec (-45)-tan(-30) x csc(-315)=
why does sec(-45) and csc(-315) both come out to square root of 2???
+118723 why does sec(-45) and csc(-315) both come out to square root of 2???
-45 degrees is in the 4th quadrant.
sec=1/cos
cos is positive in the 4th quadrant so sec is pos too.
Cos45 = 1/sqrt2
so sec45=sqrt2
--------------------------------
-315 degrees is in the first quadrant 360-315=45degrees
all the ratios are pos in the 1st quad so cosec is positive too.
cosec 45 = 1/sin45
sin 45=1/sqrt2
so
cosec45=sqrt2
---------------------------------
I hope that helps but if it doesn't just add another post on to this one.
I'm off to bed very shortly but someone else will answer you. 
+118723 why does sec(-45) and csc(-315) both come out to square root of 2???
-45 degrees is in the 4th quadrant.
sec=1/cos
cos is positive in the 4th quadrant so sec is pos too.
Cos45 = 1/sqrt2
so sec45=sqrt2
--------------------------------
-315 degrees is in the first quadrant 360-315=45degrees
all the ratios are pos in the 1st quad so cosec is positive too.
cosec 45 = 1/sin45
sin 45=1/sqrt2
so
cosec45=sqrt2
---------------------------------
I hope that helps but if it doesn't just add another post on to this one.
I'm off to bed very shortly but someone else will answer you.
