The simultaneous equations in x,y
xcosθ - ysinθ = 2
xsinθ + ycosθ = 1
are solvable for how many values of θ in the range 0<= θ < 2pi
I was told that it is for all values, using the idea of discriminants. But I haven't learnt this yet, so I am meant to use some other method. Any advice?