Solving equations using solve() function

The code below gives an empty Ans although it is clear that the solution is 0,0,0,0.

syms a b c d

res = solve(a+b,a+b+c,a+b+c+d,a)

Hence why do we get an empty answer?

Answer 1

[Torsten]

sol = solve([a+b==0,a+b+c==0,a+b+c+d==0,a==0],[a b c d]);
sol.a
sol.b
sol.c
sol.d

Best wishes

Torsten.

[AAKASH R AAKASH R]

Thanks a lot, I didn't know that a square bracket would make all the difference.