Question

calcule a soma dos 35 primeiros termos da p.a (-8,2,12)​

Answer 1

$> resolucao \\ \\ \geqslant progressao \: aritmetica \\ \\ r = a2 - a1 \\ r = 2 - ( - 8) \\ r = 2 + 8 \\ r = 10 \\ \\ \\ an = a1 + (n - 1)r \\ an = - 8 + (35 - 1)10 \\ an = - 8 + 34 \times 10 \\ an = - 8 + 340 \\ an = 332 \\ \\ \\ = = = = = = = = = = = = = = = \\ \\ \\ \geqslant a \: soma \: dos \: termos \: da \: pa \\ \\ \\ sn = \frac{(a1 + an)n}{2} \\ \\ sn = \frac{( - 8 + 332)35}{2} \\ \\ sn = \frac{324 \times 35}{2} \\ \\ sn = 162 \times 35 \\ \\ sn = 5670 \\ \\ \\ > < > < > < > < > < >$