Question

Show that (sec A - tan A)² = 1-sinA/1+sinA

​

Answer 1

LHS=(secA−tanA)

2

=(

cosA

1

−

cosA

sinA

)

2

=

(1−sin

2

A)

(1−sinA)

2

=

(1−sinA)(1+sinA)

(1−sinA)

2

=

1+sinA

1−sinA

=RHS

Hence proved.