Question

Am nevoie repede de ajutor raspundeti-mi repede la intrebarea aceasta cum se face acest calcul?
B=1+3+5+...+601 pp.
Am nevoie repede de ajutor...

Answer 1

B=1+3+5+...+601 =
=1+2+3+4+5+6+.....+600+601-2-4-6-....-600=
=601×602/2-2(1+2+3+...300)=
=601×301-2×300×301/2=
=601×301-300×301=
=301×(601-300)=
=301×301=
=301²  deci patrat perfect

Answer 2

b=(2*0+1)+(2*1+1)+(2*2+1)+...+(2*300+1)
=2(1+2+...+300)+301
=2*300*301/2+301
=300*301+301
=301(300+1)
=301*301