Question

Quantos termos tem uma P.A cujo A1 = 6, r= 2 e o ultimo termo é 32?

Answer 1

$> \: resolucao \\ \\ \geqslant \: progressao \: \: aritmetica \\ \\ a1 = 6 \\ an = 32 \\ r = 2 \\ \\ = = = = = = = = = = = = = \\ \\ an = a1 + (n - 1)r \\ 32 = 6 + (n - 1)2 \\ 32 = 6 + 2n - 2 \\ 32 = 4 + 2n \\ 32 - 4 = 2n \\ 28 = 2n \\ n = \frac{28}{2} \\ n = 14 \\ \\ \\ resposta \: > \: \: pa \: de \: 14 \: termos \\ \\ \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant \leqslant \geqslant \geqslant$

Answer 2

$\mathsf{a_1=6;~r=2;~a_n=32;~n=\,? }$

$\mathsf{a_n=a_1+(n-1)\cdot r }$

$\mathsf{ n= a_n-a_1/r+1}$

$\mathsf{n=32-6/2+1 }$

$\mathsf{n=26/2+1 }$

$\mathsf{n=13+1 }$

$\boxed{\boxed{\mathsf{n=14}} }$