Question

qual a soma dos cinquenta primeiros números naturais pares

Answer 1

a1=2

razão=2

an=a1+(n-1).r

an=2+(50-1).2

an=2+49.2

an=100

sn=(a1+an).n/2

s50=(2+100)50./2

s50=102.50/2

s50=5100/2

s50=2550

Answer 2

a1 = 0 ; r = 2

$\boxed{ \mathsf{a_{n} = a_{m} + (n -m) \cdot r}}$

0 + 49 * 2 = 98

$\boxed{\mathsf{ S_{n} = \frac{(a_{1} + a_{n} ) \cdot n}{2} }}$

98 * 50/2

2450