x+y+z=0 হলে 1x 13(x3+y3+z3) এর মান কত?
A
3xyz
B
-3xyz
C
-xyz
D
xyz
Correct Answer: xyz
দেওয়া আছে , x + y + z = 0 ........ (i) ∴(1/3) (x3 + y3 + z3) = (1/3)(x3 + y + z3 – 3xyz) + xyz = (1/3){(x + y + z) (x2 + y2 + z2 - xy - yz - zx)} + xyz = (1/3){0x(x2 + y2 + 22 - xy - yz - zx)} + xyz [(i) নং হতে] = 0 + xyz = xyz