(2cosx+sinx)/(cosx-7sinx)=-1/2 100 баллов

Question

(2cosx+sinx)/(cosx-7sinx)=-1/2
100 баллов

Answer 1

Пропорцией:
2(2cosx+sinx)=-1(cosx-7sinx)
5cosx=5sinx
sinx=cosx
x=pi/4+pi*k

Answer 2

2(2cosx+sinx)=-(cosx-7sinx)
4cosx+2sinx+cosx-7sinx=0
5cosx-5sinx=0
cosx-sinx=0
sinx-sin(π/2-x)=0
2sin(x-π/4)cosπ/4=0
sin(x-π/4)=0
x-π/4=πn
x=π/4+πn