Use the information given about the angles and to find the exact value of: 

(a) sin(α + β)

(b) cos(α + β)

(c) sin(α - β)

(d) tan (α + β)

(e) sin(2α)

(f) cos (2β)

(g) sin β/2

(h) cosα/2

cosα = 4/5, 0 < α < π/2;     cosβ = 5/13, -π/2 < β < 0