Question

answer this trigonometry question

Answer 1

$we \: know \: \: the \: \: identity\\ \frac{1 - { \tan }^{2} \alpha }{1 + { \tan }^{2} \alpha } = \cos2 \alpha \\ \\ so \: \: \frac{1 - { \tan }^{2} (45°-A) }{1 + { \tan }^{2} (45°-A) } = \cos2 (45°-A) \\ = \cos (90°-2A) = \sin 2A$

Answer 2

ʜᴏᴩᴇ ɪᴛ ʜᴇʟᴩꜱ yᴏᴜ :)

ᴍᴀʀᴋ ᴍᴇ ᴀꜱ ʙʀᴀɪɴʟɪᴇꜱᴛ :-: