Question

if the Arithmetic progression Sn= 3n+5 then the value of d is​

Answer 1

Answer:

Step-by-step explanation:

Sn =n/2 (2a+n_1)d sister solve kr lo

Answer 2

$\: \: \: \: \: \: \: \: \: \sf {\binom{s}{ \: \: \: n} = 3n + 5}$

$⇢ \: \: \sf{\binom{s}{ \: \: \: 1} = 3(1) + 5}$

$⇢ \: \: \sf{ \binom{s}{ \: \: \: 1} = 8}$

Since sum of first terms of A. P. is equal to it's first term.

$\: \: \sf{ so \: \: \: \: \: \: \: a = 8}$

$⇢ \: \: \sf{\binom{s}{ \: \: \: 2} = 3(2) + 5}$

$⇢ \: \: \sf {\binom{s}{ \: \: \: 2} = 11}$

As we know,

$\: \: \: \: \: \: \: \: \sf \purple{ \binom{a}{ \: \: \: 2} = \binom{s}{ \: \: \: 2} - \binom{s}{ \: \: \: 1}}$

$⇢ \: \sf {\binom{a}{ \: \: \: 2} = 11 - 8}$

$⇢ \sf{\: \binom{a}{ \: \: \: 2} = 3}$

$\sf{also \: \: \: \: \boxed{ \sf \green{ d = \binom{a}{ \: \: \: 2} - \binom{a}{ \: \: \: 1}} }}$

$⇢ \: \: \: \: \: \ \sf {d = 3 - 8}$

$⇢ \: \: \: \: \: \: \sf \pink {d = - 5}$