Question

упростите sin^2a-1/cos^4a+tg^2a

Answer 1

$displaystyle frac{sin^2alpha-1}{cos^4alpha} +tg^2alpha=-frac{cos^2alpha}{cos^4alpha} -1+frac{1}{cos^2alpha}=-frac{1}{cos^2alpha}-1+frac{1}{cos^2alpha} =-1$