Possible values of thita for which the point (cos thita, sin thita ) lies inside the triangle formed by lines x+y=2, x-y=1 and 6x+2y=square root of 10 are _

Possible values of theta for which the point (cos theta, sin theta ) lies inside the triangle formed by lines x+y=2, x-y=1 and 6x+2y=square root of 10 are _

Solution , 

The points (cosθ,sinθ) makes a circle  when 0≤θ<2π.

now, plot these lines  x+y = 2 , x-y=1 and 6x+2y = root10 on graph.