Question

tan 1 tan 10 tan 20 tan 70 tan 80 tan 89 =1

Answer 1

Hey There!!
Here we will use two simple concepts:

-> tan (90-x) = cot x
-> tan x cot x = 1

Now let's come to your question:
LHS

= tan 1 tan 10 tan 20 tan 70 tan 80 tan 89
= tan 1 tan 10 tan 20 tan (90-20) tan (90-10) tan (90-1)
= tan 1 tan 10 tan 20 cot 20 cot 10 cot 1
= tan 1 cot 1 tan 10 cot 10 tan 20 cot 20
= 1*1*1
= 1
= RHS


Hence Proved.


Hope it helps
Purva
Brainly Community

Answer 2

I hop it helps u a lot
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