Question

Find the number of terms in the AP 17, 29/2, 12,..., -38

Answer 1

Answer:

Given that,

a=17

common difference = a2-a1

=29/2-17

=29/2-34/2

= -5/2

an= -38

therefore, by the formula,

an=a+(n-1)d

-38=17+(n-1) (-5/2)

-38=17-5/2+(n-1)

-38=34-5/2+(n-1)

-38=29/2+(n-1)

-38×2=29+(n-1)

-76=29+(n-1)

-76-29=(n-1)

-105=(n-1)

-105+1=n

-104=n