Question 4
Consider real numbers $a,b,c$ satisfying $21ab+2bc+8ca\le12$. Find the minimum of
$$P(a,b,c)=\frac1a+\frac1b+\frac1c.$$
Editorial note: the supplied statement has domain and objective discrepancies compared with corroborating sources. Interpret reciprocals only when their denominators are nonzero; the solution separates the literal statement from explicitly labeled corrected variants.
$$P(a,b,c)=\frac1a+\frac1b+\frac1c.$$
Editorial note: the supplied statement has domain and objective discrepancies compared with corroborating sources. Interpret reciprocals only when their denominators are nonzero; the solution separates the literal statement from explicitly labeled corrected variants.