Calculation: MyMMaD - 1

DX =
( x1^²* p1+ x2^²* p2+ x3^²* p3)- (EX)^²

DX = ( x1^²* p1+ x2^²* p2+ x3^²* p3)- (EX)^² $DX$ = $(x1^{2}\cdot p1+x2^{2}\cdot p2+x3^{2}\cdot p3)-(EX)^{2}$

DX = p1* x1^²+ p2* x2^²+ p3* x3^²- EX^² $DX$ = $p1\cdot x1^{2}+p2\cdot x2^{2}+p3\cdot x3^{2}-EX^{2}$