Write the form of the following argument. Is the argument valid or invalid? A. If Ann has the flu, then Ann has a fever.
B. Ann has a fever.
C. Therefore, Ann has the flu.
A sequence S1, S2, S3, is defined recursively as follows:
a. . sk = 5 sk - 1 + (sk - 2)^2 for all integers k greater than or equal to 3
b. s1 = 4
c. s2 = 8
Use (strong) mathematical induction to prove that sn is divisible by 4 for all integers n greater than or equal to 1.