Question

determine i decimi termo do p a (3,5,7 ...)

Answer 1

an = a1 + (n - 1) x r
an = 3 + (12 - 1) x 2
an = 3 + 11 x 2
an = 3 + 22
an = 25

PA (3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25,..)

Answer 2

a10 = ?

a1 = 3
a2 = 5
r = a2 - a1
r = 5 - 3
r = 2

an = a1 + (n - 1).r
a10 = a1 + (10 - 1).r
a10 = a1 + 9r
a10 = 3 + 9.2
a10 = 3 + 18
a10 = 21