If P(n) is the statement “n3 + n is divisible by 3”, prove that P(3) is true but P(4) is not true.

Given. P(n) = n3 + n is divisible by 3


Find P(3) is true but P(4) is not true

We have P(n) = n3 + n is divisible by 3


Let’s check with P(3)


= P(3) = 33 + 3


= P(3) = 27 + 3


Therefore P(3) = 30, So it is divisible by 3


Now check with P(4)


= P(4) = 43 + 4


= P(4) = 64 + 4


Therefore P(4) = 68, So it is not divisible by 3


Hence, P(3) is true and P(4) is not true.


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