Question 3
Suppose $a,b,c,d$ are real numbers such that
$$a+b+c+d=0,\qquad abcd\left(\frac1a+\frac1b+\frac1c+\frac1d\right)=4.$$
Find $a^3+b^3+c^3+d^3$.
The supplied key conflicts with the printed equation. Use the equation as printed; the solution explains the discrepancy. All reciprocals must be defined.
$$a+b+c+d=0,\qquad abcd\left(\frac1a+\frac1b+\frac1c+\frac1d\right)=4.$$
Find $a^3+b^3+c^3+d^3$.
The supplied key conflicts with the printed equation. Use the equation as printed; the solution explains the discrepancy. All reciprocals must be defined.