3sin^ 2x - 0,5sin 4x - 4cos^2 2x= 0

3sin²x-sinxcosx-4cos²x=0/cos²x3tg²x-tgx-4=0tgx=a3a²-a-4=0D=1+48=49a1=(1-7)/6=-1⇒tgx=-1⇒x=-π/4+πk,k∈za2=(1+7)/6=4/3⇒tgx=4/3⇒x=arctg4/3+πn,n∈z