Упростите выражение и найдите его значение при t=11 п/4 cos^2t * (cos^2t-1) + 1

= cos^2 t * (1 - sin^2 t - 1) + 1 = cos^2 t * (-sin^2 t) + 1 = - (sin t * cos t) ^2 + '1=

= - 1/4 (sin 2t) ^2 + 1.

t=11pi/4;

= - 1/4 * (sin11pi/2) ^2 + 1 = - 1/4 * (sin 3 pi/2) ^2 + 1 = - 1/4 * (-1) ^2 + 1 = - 1/4 + 1 = 3/4=0,75