Question

tòm tổng của các số nguyên x ,biết :

a) -22<x<23

b) -36<x<34

Answer 1

a) -22<x<23

<=> x={-21,-20,-19,-18,....,19,20,21,22}

(-21)+(-20)+(-19)+(-18)+...+(-2)+(-1)+0+....+19+20+21+22

= 22+[(-21)+21]+[(-20)+20]+[(-19)+19]+[(-18)+18]+...+[(-2)+2]+[(-1)+1]+0

= 22+0+0+0+...+0+0

=22

b) -36<x<34

<=> x={-35,-34,-33,-32,...,32,33}

(-35)+(-34)+(-33)+...(-2)+(-1)+0+...+31+32+33

= (-35)+(-34)+[(-33)+33]+[(-32)+32]+...+[(-2)+2]+[(-1)+1]+0

=(-35)+(-34)+0+0+...+0+0

= -69

Answer 2

a) x = { -21,-20,-19,-18,-17,-16,-15,-14,-13,-12,-11,.......,23}

b) x= {-36,-35,-34,-33,-32,-31,-30,-29,-28,-27,-26,-25,......,34}