Question

cosa=3/5 cosb=5/13 find cos(a-b)​

Answer 1

Answer:

cosA=3/5 cosB=5/13

cos (A-B)

cos (3/5-5/13)

cos (39-25/13)

cos (14/13)

cos=14/13

Answer 2

Answer:

61/65

Step-by-step explanation:

cosa=3/5 then sina=4/5

cosb=5/13 then sinb=12/13

cos(a-b) = cosa*cosb+sina*sinb

=3/5*5/13+4/5*12/13

=3/13+36/65

=61/65