Sinx=cos2xsinx-1+2sin²x=0sinx=a2a²+a-1=0D=1+8=9a1=(-1-3)/4=-1⇒sinx=-1⇒x=-π/25+2πn,n∈za2=(-1+3)/4=1/2⇒sinx=1/2⇒x=(-1)^n*π/6+πk,k∈z Sinx+sin3x=o2sin2xcosx=0sin2x=0⇒2x=πn⇒x=πn/2,n∈zcosx=0⇒x=π/2+πk,k∈z Sin²x-2sin2x-5cos²x=0sin²x-4sinxcosx-5cos²x=0/cos²xtg²x-4tgx-5=0tgx=aa²-4a-5=0a1=a2=4 U a1*a2=-5a1=-1⇒tgx=-1⇒x=-π/4+πn,n∈za2=5⇒tgx=5⇒x=arctg5+πk,k∈z