Question

(b)The sum of n terms of a certain series is 3n² + 10n for all values

Of n. Find the nth term and show that the series is an
arithmetical progression
​

Answer 1

Step-by-step explanation:

sn=3n^2+10n
s1= 3(1)+10(1)=13
s2=3(2)^2+10(2)=32
s3=3(3)^2+10(3)=57
therefore:
T1=13
T2=s2-s1=19
T3=s3-s2=25
so: the series is 13,19,25 ..... hence its an A.P
where a=13
d=6
Tn=a+(n-1)d
= 13+(n-1)6
=13+6n-6
=6n+7

Answer 2

Explanation:

The nth term just mean how to work out the next number in he series. In this series of numbers, you have to square three n and add it onto 10 n to do this.

N is the term- the number it comes in the sequence.

Example:

2 3 4 5 6

2= the first terof the sequence

3= second term

4=3rd term

And so on

To work out what the next term is (6th term) you use this expression:

N+1

The first term is 2. As it is the first n=1. 1+1=2 so that works

The seco d term is 3. As it is the second term n=2. 2+1+3 so that works

And so on

This might help

But you have to do the rest