Sandbox

$NSGAPA=({\frac {\sum ^{D}GDP_{R}}{\sum ^{D}POP_{r}}})-({\frac {\sum ^{G}DP_{r}}{\sum ^{L}POP_{r}}})$

${\frac {\operatorname {d} ^{2}R}{{\operatorname {d} Q}^{2}}}<{\frac {\operatorname {d} ^{2}C}{{\operatorname {d} Q}^{2}}}$: