182k views
2 votes
Cos 30- cos 70=2 sin 50. sin 20.​

User Nelssen
by
5.9k points

1 Answer

5 votes

L.H.S=2sin(30+70/2).sin(70-30/2)

=2 sin(100/2).sin(40/2)

=2sin50.sin20

Therefore,L.H.S=R.H.S proved

User Luca Rossi
by
5.8k points