Question

sin^2x+10cos^2x=11sinxcosx

Answer 1

sin²x+10cos²x-11sinxcosx=0/cos²x
tg²x-11tgx+10=0
tgx=a
a²-11a+10=0
a1+a2=11 U a1*a2=10
a1=1⇒tgx=1⇒x=π/4+πn
a2=10⇒tgx=10⇒x=arctg10+πn