posted by Jus on .
The angle 2x lies in the fourth quadrant such that cos2x=8/17.
1.Which quadrant contains angle x?
2. What is the measure of x, in radians?
I know that angle 2x is in quadrant 4, but quadrant x...? I am not sure where it is and how to get the measure of it in radians.
Half of quadrant 4 is half of 270deg to 360 deg, or 135 to 190 deg, quadrant 2.
switch your calculator to radians
to get .470588...
press 2ndF, then cos
to get 1.08084
This would be the radian measure in the first quadrant, but you are in the fourth,
so 2pi - 1.0804 = 5.20235
but this is 2x
so x = 5.20235/2
(in degrees that would be 149.04º which is in compliance with what bobpursley told you above)