Question

Prove tat tan 10 ×tan 15×tan75× tan 80=1

Answer 1

Answer:

Step-by-step explanation:

tan 10 ×tan 15×tan75× tan 80

=tan(90-80)*tan80*tan(90-75)*tan15

=(cot80*tan80) *(cot75*tan75)

=tan80*1/tan80*tan75*1/tan75

=1*1

=1