Question Number 201140 by Calculusboy last updated on 30/Nov/23
$$\boldsymbol{{If}}\:\underset{−} {\boldsymbol{{R}}}=\boldsymbol{{x}}^{\mathrm{2}} \boldsymbol{{y}}\underset{−} {\boldsymbol{{i}}}−\mathrm{2}\boldsymbol{{y}}^{\mathrm{2}} \boldsymbol{{z}}\underset{−} {\boldsymbol{{j}}}+\boldsymbol{{xy}}^{\mathrm{2}} \boldsymbol{{z}}^{\mathrm{2}} \underset{−} {\boldsymbol{{k}}},\:\boldsymbol{{find}}\:\mid\frac{\boldsymbol{{d}}^{\mathrm{2}} \boldsymbol{{R}}}{\boldsymbol{{dx}}^{\mathrm{2}} }×\frac{\boldsymbol{{d}}^{\mathrm{2}} \boldsymbol{{R}}}{\boldsymbol{{dy}}^{\mathrm{2}} }\mid\:\: \\ $$$$\boldsymbol{{at}}\:\boldsymbol{{the}}\:\boldsymbol{{point}}\:\left(\mathrm{2},\mathrm{1},−\mathrm{2}\right) \\ $$
Answered by MM42 last updated on 30/Nov/23
$$\mathrm{16}\sqrt{\mathrm{5}\:}\:\:\checkmark \\ $$
Commented by Calculusboy last updated on 01/Dec/23
$$\boldsymbol{{please}}\:\boldsymbol{{sir}},\boldsymbol{{can}}\:\boldsymbol{{you}}\:\boldsymbol{{show}}\:\boldsymbol{{the}}\:\boldsymbol{{working}} \\ $$