find the number of positive integers less than 101 that can not be written as the difference of two squares of integers.
Answers
Answer:
25
Step-by-step explanation:
The two things here to be noted are:
1) Every odd number can be written as difference of square of two integers
Let m be an odd number
then m can be written as
m = 2k+1
or,
2) Every even number that is a multiple of 4 can be written as difference of square of two integers
Let m be an even number multiple of 4 then
m = 4k
or,
Total number of positive odd integers less than 101 (i.e. 101 is not included) = 50
Total number of positive integers divisible by 4 = 25
Therefore, total positive integers less than 101 that can be written as difference of squares of two positive integers = 50 + 25 = 75
Thus, total positive integers less than 101 that cannot be written as difference of squares of two positive integers = 100 - 75 = 25
Answer:
25
Step-by-step explanation:
The two things here to be noted are:
1) Every odd number can be written as difference of square of two integers
Let m be an odd number
then m can be written as
m = 2k+1
or, m=(k+1)^2-k^2m=(k+1)
2
−k
2
2) Every even number that is a multiple of 4 can be written as difference of square of two integers
Let m be an even number multiple of 4 then
m = 4k
or, m=(k+1)^2-(k-1)^2m=(k+1)
2
−(k−1)
2
Total number of positive odd integers less than 101 (i.e. 101 is not included) = 50
Total number of positive integers divisible by 4 = 25
Therefore, total positive integers less than 101 that can be written as difference of squares of two positive integers = 50 + 25 = 75
Thus, total positive integers less than 101 that cannot be written as difference of squares of two positive integers = 100 - 75 = 25