Eight Fundamental Identities

Question

Sec thada - Cos thada

How do I do this?

Answer 1

There is no equal sign so no identity.
sec t = 1/cos t
by definition if that helps

Answer 2

sec ( theta ) = 1 / cos ( theta )

sec ( theta ) - cos( theta ) =

[ 1 / cos ( theta ) ] - cos ( theta ) =

[ 1 - cos ^ 2 ( theta )] / cos ( theta ) =

sin ^ 2 ( theta) / cos ( theta ) =

sin ( theta ) * sin ( theta ) / cos ( theta ) =

[ sin ( theta ) / cos ( theta ) ] * sin ( theta ) =

tan ( theta ) * sin ( theta )