import math
def fun_mat_2(x, y):
    if x > -y:
        z = (x**2 - y**2)/(math.e**(x+y) - 1)
    elif x == -y:
        z = 2**x
    else:
        z = math.sin(x**2 - y**2)/(x+y)
    return float(z)