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

DX = 0.5* 1^2+ 0.5* 1^2+ p3* x3^2- EX^2$$DX$$ = $$0.5\cdot 1^{2}+0.5\cdot 1^{2}+p3\cdot x3^{2}-EX^{2}$$

DX = 0.5* 1+ 0.5* 1^2+ p3* x3^2- EX^2$$DX$$ = $$0.5\cdot 1+0.5\cdot 1^{2}+p3\cdot x3^{2}-EX^{2}$$

DX = 0.5+ 0.5* 1^2+ p3* x3^2- EX^2$$DX$$ = $$0.5+0.5\cdot 1^{2}+p3\cdot x3^{2}-EX^{2}$$

DX = 0.5+ 0.5* 1+ p3* x3^2- EX^2$$DX$$ = $$0.5+0.5\cdot 1+p3\cdot x3^{2}-EX^{2}$$

DX = 0.5+0.5+ p3* x3^2- EX^2$$DX$$ = $$0.5+0.5+p3\cdot x3^{2}-EX^{2}$$

DX = 1+ p3* x3^2- EX^2$$DX$$ = $$1+p3\cdot x3^{2}-EX^{2}$$
