Question

Prove that
Tan6tan12tan84tan78=1

Answer 1

Answer:

tan6tan12tan84tan78

tan6tan12cot(90-84)cot(90-78)

tan6tan12cot6cot12

tan6*1/tan6 * tan12*1/tan12

1*1=1

Step-by-step explanation:

Answer 2

Answer:

Step-by-step explanation:

tanФ=cot(90-Ф)

∴tan6=cot(90-6)

         =cot84=1/tan84

tan12=cot(90-12)

        =cot78=1/tan78

By subsituting the value of tan6 and tan12 in

tan6tan12tan84tan78= 1/tan84×1/tan78×tan84×tan78

                                   =1

hence proved