Prove that cos10.cos30.cos50.cos70=3/16

Steps to prove cos10.cos30.cos50.cos70=3/16

L.H.S

=cos10.cos30.cos50.cos70

=√3/2.cos10.cos50.cos70

=√3/2.cos10.cos(60-10).cos(60+10)

=√3/2.1/4.cos3(10)

=√3/2.1/4.rt3/2

=3/16

=R.H.S

Hence cos10.cos30.cos50.cos70=3/16 is proved.

Detail Information:-

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