Question

determine o 13 termo PA 9, 13,17,...)

Answer 1

Resposta:

razão=a2-a1=a3-a2 =13-9=17-13=4

a1=9

n=13

an=a1+(n-1)*r

a13=9+(13-1)*4 = 57

Answer 2

a₁₃ = a₁ + 12r

a₁₃ = 9 + 12*(4)

a₁₃ = 9 + 48

a₁₃ = 57