Question

3cos55dgree/7sin35degree - 4(cos70degree cosec20degree)/7(tan5degree tan25degree tan45degree tan65degree tan85degree)

Answer 1

Answer:

GIVEN

3cos55 / 7sin35 - 4/7(cos 70 cosec 20 ) / (tan5 tan25 tan45 tan65 tan85 )

USE

tan x = cot (90-x)

cot x = tan (90-x)

sin x = cos (90-x)

cos x = sin (90-x)

= [3 (cos55 / 7cos55)] - 4[(cos70 / sin20)] / 7 [tan5 tan25 tan45 tan65 tan85]

= (3 / 7) - 4 / 7(tan5 cot5 tan25 cot25 tan45)

= 3/7 - 4/7

= - 1 / 7

Step-by-step explanation: