Question

cot10.cot20.cot60.cot70.cot80 is equal to ?

Answer 1

Heya !

☆ here is your answer ☆

cot70.cot20× cot80. cot10× cot60

(tan90- 70).cot20 × tan (90- 80)cot10× cot 60

tan20× cot20 ×tan10× cot10×cot 60

tan20× 1/tan20 × tan 10× 1/tan10× cot 60

1 x 1 ×1/root 3

1 ×1 / root 3 = 1 /root 3

Answer 2

HEYA MATE, HERE IS UR ANSWER

$<b><i>Cot 10 × Cot 20 × cot 60 × cot 70 × cot 80$

Rearranging so that calculation becomes easier

= Cot 70 ×cot 20×cot 10× cot 80 ×cot 60

We know the identity cot (90-A)= cot A

we will use this identity here

Cot 70 ×cot (90-70)×cot 80 ×cot (90-80)×cot 60

cot 70×Tan 70×cot 80×Tan 80 ×cot 60

Now we know that Tan A=$\frac {1}{Cot\: A}$

Cot 70×$\frac {1}{cot\:70}$×Cot 80 ×$\frac {1}{cot\:80}$×cot 60

All the like terms will cancel and cot 60 will remain

We know that cot 60=$\frac {1}{\sqrt {3}}$

So ur answer is $\frac {1}{\sqrt{3}}$

$\huge\boxed{\mathbb{BE\:BRAINLY}}$