sin t*cos t*tg t=sint*cost*(sint/cost)=sin²t
sin t*cos t*ctg t-1=sint*cost*(cost/sint)-1=cos²t-1=-sin²t
sin t*cos t*tg t=sint*cost*(sint/cost)=sin²t
sin t*cos t*ctg t-1=sint*cost*(cost/sint)-1=cos²t-1=-sin²t