SOLUTION: If secx = 2, cscx < 0, find cos2x

2 is positive, the cosine and its reciprocal, 
the secant, is positive in QI and QIV

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:



find cos2x



Edwin