Question

1+tan(alpha).tan(2alpha)=sec(2alpha)​

Answer 1

Answer:

Now,

1+tanα.tan2α

=1+tanα.

1−tan

2

α

2tanα

[ Using formula for tan2α]

=

1−tan

2

α

1+tan

2

α

=

cos

2

α−sin

2

α

cos

2

α+cos

2

α

=

cos2α

1

=sec2α.