How to solve this half angle identities

90° ⩽ x ⩽ 180° is another way of saying that the angle "x" is in the II Quadrant, where sine is positive whilst cosine is negative, as you can see in your Unit Circle.  We also know that csc(x) = 2, so

now, the angle "x/2" is half the arc of the angle "x", and since the angle "x" is in the II Quadrant, we can conclude the half of that arc will be on the I Quadrant, where sine and cosine and tangent are all positive.

2 over 5

step-by-step explanation:

the 2: 3 ratio is the length of the ac segment to the cb segment total length. this implies that the ratio between segment ac length and segment ab length is 2: 5. point c is 2/5 from a to b, so the required fraction is 2/5.

-12 > a

step-by-step explanation:

-11 > 1 + a

subtract 1 from each side

-11-1 > 1-1+a

-12 > a