Question

Show that tan20º tan40º tan60º tan80º = 3

Answer 1

Answer:

we know that tan♧°cot♧°=1

given L.H.S.

tan20°tan40°tan60°tan80°

=(3)^1/2{tan20°tan40°tan80°}

we know a formula

tan♧°tan(60-♧)°tan60+♧)°=tan3♧°

so we get ,

=(3)^1/2{tan60°}

=(3)^1/2×(3)^1/2

=3

hence proved