sin (A/2)= 1/2
sec (A/2) = 10
1. cos A = 1/2, cos A = 300°
A in QIV,
sin (A/2)= (300/2)
= 150°
sin (A/2) = 1/2
2.
sin (A)=3/5 with A in QII, then sec (A/2)
cos A = (-4/5)
cos A = 2cos²(A/2) - 1
cos²(A/2) = {(1 - ⅘) / 2}
cos²(A/2) = 1/10
cos(A/2) = 1/√10
sec(A/2) = 1/cos(A/2) = 10
sec(A/2) = 10
Read more on angles:
Complete question:
For the following, assume that all the given angles are in simplest form, so that if A is in QIV you may assume that 270° < A < 360°. If sin B = - 1 / 1 with B in QIII, find the following. sin
a)If cos (A)=1/2 with A in QIV, then sin (A/2)=
b) If sin (A)=3/5 with A in QII, then sec (A/2)