Question 1202997
If secx = 2,<pre>2 is positive, the cosine and its reciprocal, 
the secant, is positive in QI and QIV</pre>cscx < 0,<pre>the sine and its reciprocal, the 
cosecant, is negative in QIII and QIV,

So angle x is in QIV

Let's draw angle x.  Since we are using x for the angle, we must use another
letter for the axis that is normally called the x-axis.  We'll make it the u
axis:

{{{drawing(400,400,-3,3,-3,3, line(-7,0,7,0), line(0,-7,0,7), 
red(arc(0,0,1,-1,0,300)),locate(2.9,0,u), green(line(1,0,1,-sqrt(3))),
locate(.5,0,1), locate(1.05,-.8,-sqrt(3)),locate(.3,-.75,2),
locate(.1,2.9,y),
line(0,0,1,-sqrt(3)) )}}}

find cos2x

{{{cos(2x)=2cos^2(x)-1=2(1/2)^2-1 = 2(1/4)-1 = 1/2-1 = -1/2}}}

Edwin</pre>