specific divisibility induction question (1 Viewer)

[ladybird775]

hey there. ive been struggling with this q for ages, i always get stuck at step 3. help will be much appreciated

prove that:
3³ⁿ + 2 ⁿ⁺² is divisible by 5

 

[lolokay]

assume true for n=k


show true for n = k+1

maybe you were only adding one to the 3 power rather than subbing in n=k+1?

 

[ladybird775]

woah, simpler than i thought. thanks a lot