By taking three different, values of n verify the truth of the following statements:
(i) If n is even, then n3 is also even.
(ii) If n is odd, then n3 is also odd.
(ii) If n leaves remainder 1 when divided by 3, then n3 also leaves 1 as remainder when divided by 3.
(iv) If a natural number n is of the form 3p+2 then n3 also a number of the same type.
(i) If n is even, then n3 is also even.
Let the three even natural numbers be 2 , 4 , 6
Cubes of these numbers ,
= 23 = 8
= 43 = 64
= 63 = 216
Hence, we can see that all cubes are even in nature.
Statement verified.
(ii) If n is odd, then n3 is also odd.
Let three odd natural numbers are = 3 , 5 , 7
Cubes of these numbers =
= 33 = 27
= 53 = 125
= 73 = 343
Hence, we can see that all cubes are odd in nature.
Statement verified.
Let three natural numbers of the form (3n+1) are = 4, 7 , 10
Cube of numbers = 43 = 64 , 73 = 343 , 103 = 1000
We can see that if we divide these numbers by 3 , we get 1 as remainder in each case.
Statement verified.
(iv) If a natural number n is of the form 3p+2 then n3 also a number of the same type.
Let three natural numbers of the form (3p+2) are = 5 , 8 , 11
Cube of these numbers = 53 = 125 , 83 = 512 , 113 = 1331
Now, we try to write these cubes in form of (3p + 2)
= 125 = 3 × 41 + 2
= 512 = 3 × 170 + 2
= 1331 = 3 × 443 + 2
Hence, statement verified.