По формулам приведения:
sin(2pi+t) = sint; tg([pi+t)=tgt.
00.
sin^2 t + cos^2 t = 1.
1) cost= √(1-sin^2 t) = √(1 - 441/841) = 20/29.
2) tgt = sint/cost = 21/29 : 20/29 = 21/20.
