Question

Efectuati:a) 5+10+15+...+1000 b)8+16+24+...+4000 c)11+22+33+...+7700 d)4+8+12+16+...+400

Answer 1

a]5+10+15+1000=30+1000=1030
b]8+16+24+4000=48+4000=4048
c]11+22+33+7700=66+7700=7766
d]4+8+12+16+400=40+400=440

Answer 2

a) 5+10+15+...+1000=5(1+2+3+.....200)=5×(200×201):2=100500

b)8+16+24+...+4000 =8(1+2+3+.....+500)=8×500×501:2=1002000

c)11+22+33+...+7700 =11(1+2+3+........+700)=11×700×701:2=2698850

d)=4(1+2+3+..............+100)=4×100×101:2=20200
toate sunt sume Gauss
la toate se da factor comun mai intai
formula de calcul este S=[(n(n+1)]:2
o suma Gauss are termenii incepind cu 1 . Termenii acestor sume sunt consecutivi