Question

упростить выражение: cos^4a-6cos²asin²a+sin^4a

Answer 1

1 - tg^4+ sin^2/cos^4 sin^2/cos^4=(1-cos^2)/cos^4= =1/cos^4 - 1/cos^2 1/ cos^4= 1+tg^4 1/cos^2=1+tg^2 1 - tg^4 + 1 +tg^4 + 1+ tg^2 = 2 + 2tg^4 +tg^2