Question

calcule o número de termos do p.a (1,5,9,...,113)

Answer 1

an=a1+(n-1).r 113=1+(n-1).4 113-1=4n-4 112+4=4n 116=4n n=116/4 n=29

Answer 2

a1 = 1
r = 4
an = 113
n = ?

an = a1 + (n-1)r

113 = 1 + (n-1)4

4n - 4 + 1 = 113

4n = 113 + 3

n = 116/4

n = 29 termos