Question

prove that : cos (81 + theta) = sin (9 - theta)

Answer 1

hey mate here is your answer
convert cos into sin and the answer is 0
cos(90-Q )
I hope it will help you to find your answer
thank you

Answer 2

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