Find the sum to 20 terms of 0.15,0.015,0.0015,..

Find the sum to 20 terms of the AP 10,7,4,……

What is the sum of first 20 natural. numbers? b) Find the sum of .first 20 terms of 4,8 , 12,.... c) If 3 is added to each term in the above sequence, write down the algebraic expression of the new sequence. d) Find the sum of first 20 terms of the new sequence.

Consider the A.P. 18,15,12.... Find the sum to n terms of the A.P.

Find the sum to 15 terms of the AP 3,7,11,……

Find the sum to n terms of the series 3+15+35+63+ cdots .

n, 3n, 5n,... is an arithmetic sequence. a) What is the common difference? b) Prove that the sum of first 'n' terms of this sequence is n^(3) . c) Then find the sum of 15 terms of the sequence 15,45,75,…..

Write the algebraic form of the sequence and its sum of n terms. 5,10,15,20, ...

Find the sum to n terms of a series is 7n^2-5n . Show that it is an AP and find the 15^th term.

What is sum of the first.20 natural numbers? ii) The algebraic form of an arithmetic sequence is 6n+5. Find the sum of the first 20 terms of this sequence.

Algebraic form of an arithmetic sequence is 6n+3 a) Find the sum of first 20 terms of the sequence: b) Write the algebraic expression of the sum.