Question

Calcule o nuemro de termos da pa (5,10 ...785) dado a an=a1+(n-1).r

Answer 1

$A_{n} = a_{1} + (n -1) . r$

785 = 5 + (n -1) .5
780/5 = n - 1
157 = n

Answer 2

Bom Dia!

Dados:

a1 → 5

an → 785

r → a2-a1 → 10-5 = 5

n → ?

________________

An=a1+(n-1)·r

785=5+(n-1)·5

785=5+5n-5

785-5n=5-5

-5n=0-785

-5n=-785 (-1)

5n=785

n=785/5

n=157

_______________

Att;Guilherme Lima