-5sinxcosx+=0

Question

-5sinxcosx+=0

Answer 1

Разделим на cos²x≠0
tg²x-5tgx+4=0
tgx=a
a²-5a+4=0
a1+a2=5 U a1*a2=4
a1=1⇒tgx=1⇒x=π/4+πn
a2=4⇒tgx=4⇒x=arctg4+πn