Question

Упростить (/- дробь)
tg2a*tga/tg2a-tga

Answer 1

$frac{tg2acdot tga}{tg2a-tga} = frac{sin2acdot sina}{cos2acdot cosacdot (frac{sin2a}{cos2a}-frac{sina}{cosa})}=\\=frac{sin2acdot sinacdot cos2acdot cosa}{cos2acdot cosacdot (sin2acdot cosa-cos2acdot cosa)} =frac{sin2acdot sina}{sin(2a-a)} = frac{sin2acdot sina}{sina} =sin2a$