Question

(1+2+3+...+14):(1+2+3+...+6) E pentru fratele meu mai mic si eu nu mai le tin minte

Answer 1

(1+2+3+.....+14):(1+2+3+....+6)=                   ( S=nx(n+1):2 )
(14x15:2):(6x7:2)=
(210:2):(42:2)=
105:21=5

Answer 2

[tex](1+2+3+...+14):(1+2+3+...+6)= \\ = \frac{14*15}{2}: \frac{6*7}{2}= \\ = \frac{14*15}{\not2}* \frac{\not2}{6*7}= \\ = \frac{14*15}{6*7}= \frac{210}{42}=5 \\ Am~folosit~formula~de~la~suma~lui~Gauss: \\ 1+2+3+...+n= \frac{n(n+1)}{2} [/tex]