A. For the following problems, assume that all given angles are in simplest form, so that if A is in QIV you may assume that 270°<A<360°.

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)

c) If sin (A)=-4/3 with A in QIII, then win (A/2)

B. Let CSC A=(sqrt (13))/2 with A in QI and find the cos (2A)