I stuck with these 2 problems for a long time not sure that it is defined or not

Question 1: Give all solutions, if any, of

x + y =1

sin(x - y) =1/2

with 0 less than or equal to X and X is less than or equal to 3

Question 2: Give all solutions, if any, of

sinx +siny = -1

sinx - siny + 4cosz =1

sinx + siny + 2cosz =2

For this problem; after I did Gauss Ellimination, I got

[1 1 0 -1]

[0 1 -2 -1]

[0 0 1 3/2] Then z=3/2, y=2, x=-3

but siny=sin2=undefined and sinx=sin(-3)=undefined

I am not sure what I have done wrong, please help

Thank you