Dear Friends,

I have a question about the sine product formulae.

As far as I know, Euler thinks the function as a polynomial of order, and writes it by using its roots as

or equivalently

........(1)

for some constants .

From the fact that

the constant in (1) is computed to be .

Hence

........(2)

My question comes at this point.

How I can be sure that the right-hand side of (2) gives , not ?