Question

considere a função f:N ->N tal que f(0) =0 e f(0+1)= f(n)+n+1 para todo n∃N o valor de f(4) é

Answer 1

cheap the neighboring

Answer 2

f(0+1)=f(1)
f(1)=f(0)+0+1
~~f(1)=1
~~f(0)=0

f(1)=f(4)+4+1
1=f(4)+5
f(4)=-4