= (1-cos^2 2a) + cos^2 2a + (1/cos^2 2a)= 1 - cos^2 2a + cos^2 2a + 1/cos^2 2a= 1 + 1/cos^2 2a= 1 + sec^2 2a
= (1-cos^2 2a) + cos^2 2a + (1/cos^2 2a)
= 1 - cos^2 2a + cos^2 2a + 1/cos^2 2a
= 1 + 1/cos^2 2a
= 1 + sec^2 2a