Maths Question (F.4)
回答 (3)
2007-12-19 6:23 am
✔ 最佳答案
odd number 即係單數 eg. 1 , 3, 5 , 7, 9 , 等等都係單數
1^2 係 = 1
3^2 係 = 9
5^2 係 =25
7^ 2 係 =49
9^2 係 =81
1, 9, 25, 49 同 81都係單數啦 !
so the square of any odd number is also an odd number...!
參考: 自己
2007-12-19 6:28 am
let y be an even number,
then y +1 is a odd number
square of any odd number = (y+1)^2
= y^2 +2y + 1
= y (y +2) + 1
as (y + 2 is an even number, y (y +2 ) is also even number
and y (y +2) + 1 must be an odd number..
then y +1 is a odd number
square of any odd number = (y+1)^2
= y^2 +2y + 1
= y (y +2) + 1
as (y + 2 is an even number, y (y +2 ) is also even number
and y (y +2) + 1 must be an odd number..
2007-12-19 6:27 am
1.1x1=1
2.3x3=9
3.5x5=25
4.7x7=49
5.9x9=81
6.11x11=121
7.13x13=169
8.15x15=225
9.17x17=289
10.19x19=361
All of this square are odd no.
2.3x3=9
3.5x5=25
4.7x7=49
5.9x9=81
6.11x11=121
7.13x13=169
8.15x15=225
9.17x17=289
10.19x19=361
All of this square are odd no.
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