Question

If α and B are the measures of two first quadrants angles and sinα=4/5 and sin B= 5/13 find sin (α+B)

Answer 1

Wait, its same http://openstudy.com/users/viictor#/updates/4fba1289e4b05565342ef173

Answer 2

sinα = 4/5 => cos α = 3/5
sinB = 5/13 => cosB = 12/13

sin (α+B) = sinαcosB + cosαsinB
= (4/5)(12/13) + (3/5)(5/13)
= ... ?

Answer 3

63/65?