1)sin^2t-sint=0 2)4 cos ^2t-1=0 решить, ))

1
sint(sint-1)=0
sint=0⇒t=πn,n∈z
sint=1⇒t=π/2+2πk,k∈z
2
(2cost-1)(2cost+1)=0
cost=1/2⇒t=+_π/3+2πn,n∈z
cost=-1/2⇒t=+-2π/3+2πk,k∈z