Question

Evaluate i wanna get it with best and minute solutions

Answer 1

solution :

****************************
i ) cos 70 = cos ( 90 - 20 ) = sin 20°

ii ) sinAcosecA = 1

iii ) tan5 = tan( 90-85) = cot85

iv ) tanAcotA = 1

v ) tan 25 = tan(90-65) = cot 65

vi ) tan 30° = 1/√3

**********************************

Now ,

a) cos70cosec20

= sin20cosec20

= 1 -----( 1 )

ii ) (tan5tan25tan30tan65tan85)

Rearranging the terms, we get

= tan5tan85tan25tan65tan30

= (cot85tan85)(cot65tan65)tan30

= 1 × 1 × 1/√3

= 1/√3 -----( 2 )

iii ) According to the problem given,

( 1 )/( 2 )

= 1/( 1/√3 )

= √3

••••