Question

4. Write the terms of the sequence 5*(1+6), 10%(2+6), 15x(3+6), 20%(4+6) ..... in
the form : first term 5x1(1+6), second term 5x2(2+6). Write its algebra.​

Answer 1

Step-by-step explanation:

Given arithmetic sequence is 9, 15, 21,.

First term = a = 9

Common difference = d =15 9 = 6

(A) For natural number n

nth term = [(n−1)x6]+9=6n+3 where n=1,2,3,

Hence algebraic form of the sequence 9,15,21,. is x

n

=6n+3.

(B) nth term =6n+3

25

th

term =6(25)+3=150+3=153

(C) Sum of first n terms is given by,

S

n

=

2

1

n[X

1

+X

n

]

Sum of 24 terms is

S

24

=

2

1

n[X

1

+X

2

4]=

2

25

[9+147]=1950