Question

Evaluate without using trignometric tables
Tan80°tan10°

Answer 1

tan80°tan10°

We can write tan10° as,

tan(90-80)

=cot80

Now,

Putting cot80 in place of tan10,we get:

tan80.cot80

=1 [tan∅=1/cot∅]

Answer 2

Step-by-step explanation:

Hi,

Tan80° × Tan10°

Tan(90-80°) × Tan10°

Cot10° × Tan10°

Cot10° × 1/ Cot10°

1

Hope it will help you :)