ISI2016-DCG-29

Question

The condition that ensures that the roots of the equation $x^{3}-px^{2}+qx-r=0$ are in  H.P. is

• A. $r^{2}-9pqr+q^{3}=0$
• B. $27r^{2}-9pqr+3q^{3}=0$
• C. $3r^{3}-27pqr-9q^{3}=0$
• D. $27r^{2}-9pqr+2q^{3}=0$

Comments

see here,same question https://gateoverflow.in/321195/isi2015-dcg-29