1/1.3 1/3.5 1/5.7 ... 1/(2n-1)(2n 1) = n/2n 1?

let me fix it for you

should say:
1/(1*3) + 1/(3*5) + 1/(5*7) + ... + 1/(2n-1)(2n + 1) = n/(2n + 1)

Now what about it ???
Are you trying to prove it is true?
Try Induction.

1/(1*3) + 1/(3*5) + 1/(5*7) + ... + 1/(2n-1)(2n + 1) = n/(2n + 1)

To determine whether the expression 1/(2n-1)(2n+1) is equal to n/(2n+1), we can simplify both expressions and compare them.

Let's simplify the expression 1/(2n-1)(2n+1):

By applying the concept of multiplication in algebra, we can rewrite it as 1/[(2n-1)*(2n+1)].

To simplify further, we can use the distributive property to multiply (2n-1) with (2n+1):

1/[(2n)*(2n) + 2n - 2n - 1*(2n+1)].

This simplifies to:

1/(4n^2 + 2n - 2n -1),

which further reduces to:

1/(4n^2 - 1).

Now let's simplify the expression n/(2n+1):

This expression is already in its simplest form, so we do not need to perform any additional steps.

Now we can compare the simplified expressions:

1/(4n^2 - 1) vs. n/(2n+1).

By observing both expressions, we can see that they are not equal. Therefore, the expression 1/(2n-1)(2n+1) is not equivalent to n/(2n+1).

I have explained how to get the answer to this question by simplifying both expressions and comparing them.