Q. prove that the even power of a natural number cannot be equal to 8k−3
Assume Even Power Property: Assume that an even power of a natural number can be written as 8k−3. Let n be a natural number and 2m be its even power, where m is a natural number. So, we have n2m=8k−3.
Consider Remainders: Consider the possible remainders when an even power of a natural number is divided by 8. An even power of a natural number is always a perfect square, and perfect squares can only have remainders of 0, 1, or 4 when divided by 8.
Check Remainder of 8k−3: Now, let's check the remainder when 8k−3 is divided by 8.8k−3 divided by 8 gives a remainder of −3, which is equivalent to a remainder of 5 (since −3mod8=5).
Evaluate Remainder Validity: We see that a remainder of 5 is not possible for an even power of a natural number (as it can only be 0, 1, or 4).Therefore, n2m cannot be equal to 8k−3.
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