Question No.5 (i)

Lesson#6
Question No.5 (i)
Q5: Prove that:
(i): cos 20° cos 40° cos 60° cos 80°=1/16
Ans: =1/16=R.H.S
Example 5 (page 335) solve yourself.
Trigonometric Identities
Chapter No 10
Exercise No 10.4
Mathematics
part 1