Question

soma dos 100 termos da P.A. (-2,0,2,...)

soma dos 200 termos da P.A. (-5,0,5,10,...)​

Answer 1

$\geqslant resolucao \\ \\ \geqslant progressao \: aritmetica \\ \\ > soma \: dos \: 100 \: termos \: da \: pa \: ( - 2.0.2...) \\ \\ r = a2 - a1 \\ r = 0 - ( - 2) \\ r = 0 + 2 \\ r = 2 \\ \\ a100 = a1 + 99r \\ a100 = - 2 + 99 \times 2 \\ a100 = - 2 + 198 \\ a100 = 196 \\ \\ \\ sn = \frac{(a1 + an)n}{2} \\ \\ sn = \frac{( - 2 + 196)100}{2} \\ \\ sn = \frac{194 \times 100}{2} \\ \\ sn = 194 \times 50 \\ \\ sn = 9700 \\ \\ \\ \\ = = = = = = = = = = = = = = = = = = = = = = = = = \\ \\ \\ > soma \: dos \: 200 \: termos \: da \: pa \: ( - 5.0.5.10....) \\ \\ r = a2 - a1 \\ r = 0 - ( - 5) \\ r = 0 + 5 \\ r = 5 \\ \\ a200 = a1 + 199r \\ a200 = - 5 + 199 \times 5 \\ a200 = - 5 + 995 \\ a200 = 990 \\ \\ \\ sn = \frac{(a1 + an)n}{2} \\ \\ sn = \frac{( - 5 + 990)200}{2} \\ \\ sn = \frac{985 \times 200}{2} \\ \\ sn = 985 \times 100 \\ \\ sn = 98500 \\ \\ > < > < > < > < > < > < > < >$