Question

c) Calculaţi suma S= 1 + 3 + 5 + ... +99.​

Answer 1

Explicație pas cu pas:

$S= \frac{99 \times (99 + 1)}{2} \\ \\ S= \frac{ 99 \times 100}{2} \\ \\ S= \frac{9900}{2} \\ \\ \green{ S= 4950}$

Am folosit formula lui Gauss:

$\red{1 + 2 + 3 + ... + n = \frac{n \times (n + 1)}{2} }$

Answer 2

S=1+2+3+5+....+99=?

Aplicăm formula lui Gauss: n x ( n + 1 ) : 2

99x(99+1):2=99x100:2=9900:2=4950