Dear Student,
From the above image, we have
Now, y has coefficient -1, which can be written as (-1)2n+1 for n ∈ Z.
As for n = 1, we have (-1)2n+1 = (-1)2.1+1 = (-1)3 = -1
similarly, for n = 2, 3 and so on (-1)2n+1 = -1 because (2n + 1) is an odd number.
So, we write (-1)2n+1 on the place of -1 as:
Again, from the image shown above, it is clear that
Again, y has a coefficient equal to +1.
Now, +1 can be written as: (-1)2n where n ∈ Z.
As for n = 1, we have (-1)2n = (-1)2.(1) = (-1)2 = 1
similarly, for n = 2, 3 and so on (-1)2n = 1 because 2n is an even number.
So, we get
The joining of two equation is illustrated as:
Hope you get it!!
Regards