Q20 of 30 Page 36

Check whether 4n can end with the digit 0 for any natural number n.

If 4n is divisible by 10 then it can end with digit zero


If it is divisible by 10 it has to be divisible by 5 and 2 both


The prime factorization of 14 is 2 × 2 which is 22


4n = (22)n = 22n


Observe that 22n is divisible by 2 (because and 22n–1 is intan eger for n≥1) but not by 5 because there is no 5 in prithe me factorization of 4


Hence 4n is not divisible by 10


Hence 4n eedoesnot end with 0 for any natural number n


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