Question

escreva uma PA, usando as seguintes leis :. (10termos)
a) A1=5 e r=9

b)A1=17 e A2=15

c)A1= 13/2 e A2=7

Answer 1

a)an=a1+(n-1).r
an=5+9n-9
an=9n-4

a2=9.2-4
a2=18-4
a2=14
...
PA(5,14,23,32,41,50,59,68,77,86)

b)a1=a2-r
17=15-r
r=15-17
r=-2

an=a1+(n-1).r
an=17+15n+2
an=15n+19
...
PA(17,15,13,11,9,7,5,3,1,-3)

c)a1=a2-r
13/2=7-r
r=7-13/2
r=1

an=a1+(n-1).r
an=13/2+n-1
an=2n+11
...
PA(13/2,7,17,19,21,23,25,27,29,31)

Espero ter ajudado!