Question

I need answer woth definition mainly i need definitions ​

Answer 1

Step-by-step explanation:

Given the sum of first n terms of A.P is 210 and sum of its first (n – 1) terms is 171. Also first term is 3

• Since in an A.P there are n terms. By taking out (n – 1) terms we get the last term.
• So the last term will be 210 – 171 = 39
• Now Sn = n/2 (a + l) (where l is last term)
•         210 = n/2 (3 + 39)
•         420 = 42 n
• Or n = 420 / 42
• Or n = 10
• Now since A.P has n terms we know sum to n terms of an A.P will be
• Sn = n/2 (2a + (n -1 )d)
• 210 = 10/2 (2 x 3 + (10 – 1) d)
• 210 = 5(6 + 9d)
• 210 /5 = 6 + 9 d
• 42 = 6 + 9d
• Or 9d = 36
• Or d = 4
• Now since common difference is 4 the arithmetic progression or A.P will be 3,7,11,15,19,23,27,31,35,and 39

Reference link will be

https://brainly.in/question/12304646

Answer 2

answer is given in the attachment