Question

Докажите тождество (tg)^2 a-(sin)^2 a=(sin)^2 a (tg)^2 a

Answer 1

tg²a- sin²a   =   sin²a * tg²a
sin²a/cos²a - sin²a = sin²a * tg²a
sin²a*(1/cos²a -1)  =  sin²a * tg²a
sin²a*((1-cos²a)/cos²a) =sin²a*tg²a
sin²a *(sin²a/cos²a) = sin²a * tg²a
sin²a * tg²a = sin²a * tg²a