Solve the following problem:
In a binary communication system two equiprobable messages s1 = (1, 1) and s2 = (-1, -1) are used. The received signal is r = s + n, where n = (n1, n2). It is assumed that n1 and n2 are independent and each is distributed according to
f(n) = 1/2 e-|n|
Determine and plot the decision regions D1 and D2 in this communication scheme.