The angle of intersection of the circles x2+y2=4 and x2+y2=2x+2y, is

We know that the angle of intersection of two circles of radii r1 and r2 is given bycos⁡θ=r12+r22−d22r1r2,where d is the distance between  their centresHere, r1=2,r2=2 and d=2.∴ cos⁡θ=4+2−22×2×2=12⇒θ=π4