Show that:
`tan 10^(@)tan 15^(@) tan 75^(@)tan 80^(@)=1`

Show that : (i) tan 10^(@) tan 15^(@) tan 75^(@) tan 80^(@) = 1 (ii) sin 42^(@) sec 48^(@) + cos 42^(@) "cosec 48"^(@) = 2

Prove that: tan10^(@) tan20^(@)tan70^(@)tan80^(@)=1

tan 75 ^(@) - tan 30^(@)- tan 75^(@) tan 30^(@) =1.

Show that tan48^(@) tan 23^(@) tan 42^(@) tan 67^(@) =1 .

tan 20^(@) tan 40^(@) tan 80^(@) = tan 60^(@)

tan 6 ^(@) tan 42 ^(@) tan 66 ^(@) tan 78^(@) =1

Prove that: (a) tan 20^(@)tan40^(@)tan60^(@)tan 80^(@)=3 (b) tan9^(@)-tan27^(@)-tan63^(@)+tan81^(@)=4

Prove that: tan10^(@)tan50^(@)+tan50^(@)tan70^(@)+tan70^(@)tan170^(@)=3

Shown that : tan48^(@)tan23^(@)tan42^(@)tan67^(@)=1

Without using trigonometric tables , prove that : (i) tan20^(@)tan40^(@) tan45^(@)tan50^(@)tan70^(@)=1 (ii) tan1^(@) tan2^(@)tan60^(@)tan88^(@)tan89^(@)=sqrt(3) (iii) cot5^(@)cot10^(@)cot30^(@)cot80^(@)cot85^(@)=sqrt(3) (iv) 4sin10^(@)sin20^(@)sin30^(@)sec70^(@)sec80^(@)=2