Question

1) cos (81°+0) = sin (90 - 0)​

Answer 1

Step-by-step explanation:

cos ( 81 +theta ) = sin (9- theta )

angle of cos is = 81- theta

so,

LHS= sin {90- (81+ theta) } [ sin( 90- theta )= cos theta]

= sin ( 90-81- theta)

= sin ( 9 - theta )

RHS = sin (90- theta)

therefore, RHS =LHS

HENCE PROVED

HOPE THIS HELPS U