Răspuns :
Aplicam formula S=(U+P)·nr termeni supra 2 si nr termeni=(U-P):R+1.
nr termeni=(199-1):2+1=198:2+1=99+1=100
x=200·100 supra 2
x=20000 supra 2
x=10000
nr termeni=(199-1):2+1=198:2+1=99+1=100
x=200·100 supra 2
x=20000 supra 2
x=10000
x=1+3+...+197+199
Daca ne gindim atent si adunam fiecare nr. de la-nceput cu sfirsit atunci obtinem
x=1+199 + 3+197+...+99+101
x=200+200+...+200 ( de [99+1] / 2) ori
x=200 · 50 =10000