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[Anum96]

if you have ANY +ve integer k, doesnt matter if it is odd or even, the value '2k' is always even.
since 2k is even, 2k+1 is odd.
any product of an odd and an even number is even.
so 2*odd = even
2(2k + 1) = even i.e. double the odd number = 4k + 2

Thank you so much!

 

[Anum96]

 

[***amd***]

View attachment 58903

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because gradient (m) of any line perpendicular to a line with m = x is '-1/x' (-ve reciprocal)
u have 4 lines, opp two parallel to each other and other 2 perp to them.
lets take gradient of any 2 opp lines as x
gradient of the other 2 lines = -1/x

product of all 4 gradients = x * x * -1/x * -1/x = 1

 

[Anum96]

1
because gradient (m) of any line perpendicular to a line with m = x is '-1/x' (-ve reciprocal)
u have 4 lines, opp two parallel to each other and other 2 perp to them.
lets take gradient of any 2 opp lines as x
gradient of the other 2 lines = -1/x

product of all 4 gradients = x * x * -1/x * -1/x = 1

Thank you!