1.If 0<θ<π20 < \theta < \dfrac{\pi}{2}0<θ<2π, x=∑n=0∞cos2nθx = \sum\limits_{n=0}^{\infty} \cos^{2n} \thetax=n=0∑∞cos2nθ, y=∑n=0∞sin2nθy = \sum\limits_{n=0}^{\infty} \sin^{2n} \thetay=n=0∑∞sin2nθ and z=∑n=0∞cos2nθ⋅sin2nθz = \sum\limits_{n=0}^{\infty} \cos^{2n} \theta \cdot \sin^{2n} \thetaz=n=0∑∞cos2nθ⋅sin2nθ, thena.xyz=(x+y)zxyz = (x + y)zxyz=(x+y)zb.xy+yz+zx=zxy + yz + zx = zxy+yz+zx=zc.xyz=(x+y)zxyz = (x + y)zxyz=(x+y)zd.xyz=4xyz = 4xyz=4Login to continueOnly logged in users canattempt or see the solution.