Question

1)O centésimo termo da P.A.(3,9,15...) é: a)500 b)581 c)591 d)597

Answer 1

$<var>\bigcirc \ P.A. = (3, 9, 15, ...)</var>$

 

$<var>\cdot \ a_{100} = ?</var>$

 

$<var>\cdot \ a_1 = 3</var>$

 

$<var>\cdot \ n = 100</var>$

 

$<var>\cdot \ r = 6</var>$ , pois  $<var>9 - 3 = 6</var>$  ou $<var>15 - 9 = 6</var>$

 

$<var>\blacktriangleright a_n = a_1 + (n - 1) \cdot r</var>$ define o termo geral da P.A.:

 

$<var>a_{100} = 3 + (100 - 1) \cdot 6</var>$

 

$<var>a_{100} = 3 + 99 \cdot 6</var>$

 

$<var>a_{100} = 3 + 594</var>$

 

$<var>a_{100} = 597</var>$

 

Opção d) 597