Respected authorities how will we know in which quadrant sin x/2 cosx/2 and tan x/2 positive or negative?
sin(x/2) is positive in 1st and 2nd quadrant
and sin(x/2) is negetive in 3rd and 4th quadrant
cos(x/2) is positive in 1st and 4th quadrant
and cos(x/2) is negetive in 3rd and 2nd quadrant
tan(x/2) is positive in 1st and 3rd quadrant
and sin(x/2) is negetive in 2nd and 4th quadrant