Task 15. From the first step of the algorithm, show that f is a factor of r2. Task 16. From the second step of the algorithm, show that f is a factor of r3. Task 17. From the third step of the algorithm, show that f is a factor of 1. Task 18. Conclude that f = 1. Does this mean that ro and ri are relatively prime? Task 19. (a) Do you think that the above steps prove the lemma 27 Mathematicians wou find the steps in tasks 15 to 18 a more rigorous argument than the steps in tasks 11 to 1 (b) Can you find some issues with the proof? (c) Do tasks 15 to 18 feel fundamentally different