Final answer:
To find the potential everywhere inside and outside the sphere, we need to express cos(2θ) as a linear combination of Legendre polynomials. By substituting this expression for cos(2θ) into the given potential function, we can obtain the potential everywhere inside and outside the sphere.
Step-by-step explanation:
To find the potential everywhere inside and outside the sphere, we need to express cos(2θ) as a linear combination of Legendre polynomials. We can do this by using the Legendre polynomial expansion of cos(θ), which is given by:
cos(θ) = P₀(cos(θ)) + 2P₂(cos(θ)) + 2P₄(cos(θ)) + ...
Using this expansion, we can express cos(2θ) as:
cos(2θ) = 2cos²(θ) - 1 = 2[P₀(cos(θ)) + P₂(cos(θ)) + P₄(cos(θ)) + ...]² - 1.
By substituting this expression for cos(2θ) into the given potential function V(r,θ) = V₀cos(2θ), we can obtain the potential everywhere inside and outside the sphere.