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

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

Prove that tan40^(@) + 2tan10^(@) = tan50^(@)

Evaluate tan20^(@)tan25^(@)tan65^(@)tan70^(@) .

(tan8 0^(@)-tan1 0^(@))/tan70^(@)

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

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

Prove that: i) tan36^(@)+tan9^(@)+tan36^(@)tan9^(@)=1

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

Prove that : tan 70^(@) = tan 20^(@) + 2 tan 50^(@)

If 2a=2tan10^(@)+tan50^(@), 2b=tan20^(@)+tan50^(@) 2c=2tan10^(@)+tan70^(@), 2d=tan20^(@)+tan70^(@) Then which of the following is/are correct ?