1-Prove-by-recurrence-that-so-n-N-and-R-cos-n-isin-n-cos-n-isin-n-2-Prove-that-U-n-1-1-5-U-n-2-6-and-U-1-5-2-is-decrease-

Question Number 158984 by LEKOUMA last updated on 11/Nov/21

1 . P r o v e b y r e c u r r e n c e t h a t

s o n \in N a n d θ \in R

(\cos (n θ) + i \sin (n θ) = \cos (n θ) + i \sin (n θ)

2 . P r o v e t h a t U_{n + 1} = \frac{1}{5} (U_{n}^{2} + 6) a n d

U_{1} = \frac{5}{2}, i s d e c r e a s e