The sequence an=2an−1−2an−2a_n = 2a_{n-1} - 2a_{n-2}an=2an−1−2an−2 has roots 1±i1 \pm i1±i. Express the roots in polar form ρ(cosθ+isinθ)\rho(\cos \theta + i \sin \theta)ρ(cosθ+isinθ).
ρ=2,θ=π/4\rho = \sqrt{2}, \theta = \pi/4ρ=2,θ=π/4
ρ=2,θ=π/2\rho = 2, \theta = \pi/2ρ=2,θ=π/2
ρ=1,θ=π/4\rho = 1, \theta = \pi/4ρ=1,θ=π/4
ρ=2,θ=π/2\rho = \sqrt{2}, \theta = \pi/2ρ=2,θ=π/2