Looking for a proof regarding ( particular between the 2$^{nd}$ and 3$^{rd}$ ):
$$sec(2A) = \frac{1+\frac{\sin^{2}A}{\cos^{2}A}}{1-\frac{\sin^{2}A}{\cos^{2}A}} = \frac{\cos^{2}A+\sin^{2}A}{\cos^{2}A-\sin^{2}A}$$
Trying to show that sec(2A) indeed the final part shown there (that's the proposition).

Question

Looking for a proof regarding ( particular between the 2$^{nd}$ and 3$^{rd}$ ):
$$sec(2A) = \frac{1+\frac{\sin^{2}A}{\cos^{2}A}}{1-\frac{\sin^{2}A}{\cos^{2}A}} = \frac{\cos^{2}A+\sin^{2}A}{\cos^{2}A-\sin^{2}A}$$
Trying to show that sec(2A) indeed the final part shown there (that's the proposition).

anonymous · Answer

To clarify, I got as far as the middle  ;-)

foolaroundmath · Answer

Try : Take $$\cos^{2}A$$ as LCM in both numerator and the denominator.

anonymous · Answer

o_O  LCM = ?

terenzreignz · Answer

Well, what I like to do about these "irritating" complex fractions is reduce it to just one fraction :)

anonymous · Answer

Oh...  Least Common Multiple...  Wow I haven't used that term in...

terenzreignz · Answer

Careful, you might reveal your age... :P

anonymous · Answer

haha