Question

ПОМОГИТЕ, пожалуйста sin^4*x+cos^4*x=7/8

Answer 1

 7/8=(1-cos^2)^2+cos^4=1-2cos^2+2cos^4

cos^4-cos^2+1/16=0

(cos^2-1/2)^2=3/16

cos^2=1/2+-sqrt(3)/4=(4+-2sqrt(3))/8=(1+-sqrt(3))^2 /8

cos=+-(1+-sqrt(3))/(2sqrt(2))