Sin^2x-6sinx*cosx+5cos^2x=0

Question

Sin^2x-6sinx*cosx+5cos^2x=0

Answer 1

Sin2x-3(2cosxsinx)+5cos2x=0
sin2x-3sin2x+5cos2x=0
5cos2x-2sin2x=0 :cos2x
5-2tgx=0
2tgx=5
tgx=2.5
x=arctg 2,5