Find sin (x/2) , cos (x/2) , and tan (x/2) from the given information: cos(x) = − 7/25 , 180° < x < 270°.

Question

Find sin(x/2), cos(x/2), and tan(x/2) from the given information:

cos(x)=-7/25, 180° < x < 270°

Since cos(x)=-7/25 and 180° < x < 270°, the angle is in quadrant 3, and the half-angle is the range

90°< (x/2) < ?. So, the half-angle is in quadrant 11.

So, my question is what would the question mark in 90° < (x/2) < ? be. Thank you.

Answer 1

cos(x)=-7/25=-.28

x=106.26°

I got quad2.