CHAPTER 4. TRIGONOMETRY431.
O
N í~åO
N í~å
Åçë
OOα
+α
−
α= ==
432.
O
N í~åO
Oí~å
í~å
− Oαα
α= ==
433.
O
Oí~åO
N í~å
ÅçíOαα
−
α= ==
=
=
4.14 Transforming of Trigonometric
Expressions to Product
=
434.
O
Åçë
Oëáå ëáå Oëáå
α+β α−β
α+ β= ==- O
ëáå
Oëáå ëáå OÅçë
α+β α−β
α− β= ==- O
Åçë
OÅçë Åçë OÅçë
α+β α−β
α+ β= ==- O
ëáå
OÅçë Åçë Oëáå
α+β α−β
α− β=− ==