Question

solve it ..

step by step

Answer 1

=cot(90*-85*) . cot (90*-65*) . tan 30*.tan 65*.tan 85*
=cot 85* . cot 65* . tan 30*.tan 65*.tan 85*
=1/tan 85* . 1/tan 65* . tan 30* . tan 65*. tan 85*
=1 . 1 .tan 30*
= tan 30*
=1/√3. ans

Answer 2

cot(90-85)×cot(90-65)×tan30×tan65×tan85
(cot(90-x)=cot x):cot85×cot65×tan30×tan65×tan85
1/tan85 × 1/tan65 × tan30 × tan65 × tan85
1×1×tan 30
tan 30