Question

Find the sum of the first 50 terms In An = 3n + 2

Answer 1

hello : 
this  arithmetic  sequence  the first term is : A1 = 3(1)+2=5
and common difference is  r = 3
the sum of the first 50 terms  is : S50 = 50/2(A1  + A50)
A50 = 3(50)+2 = 152
 S50 = 50/2(5  + 152)= 3925

Answer 2

Answer with Step-by-step explanation:

The sum of first n terms of an arithmetic progression is given by:

$S(n)=\dfrac{n}{2}\times (A1+An)$

We are given n=50 and we have to find S(50)

$S(50)=\dfrac{50}{2}\times (A1+A50)$

A1=3×1+2=5

A50=3×50+2=152

$S(50)=\dfrac{50}{2}\times (5+152)$

S(50)=25×157

        =3,925

Hence, sum of the first 50 terms in An = 3n + 2  is:

3,925