if the nth term of an a.p. is(2n+1), find the sum of first n term of the a.p.
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Hey !!!
nth term of an A.P is (2n+ 1 )
Hence,
a₁ =2 * 1 + 1
a₁= 3
similarly ,
a₂ = 2* 2 + 1
a₂= 5
∵ d = a₂ - a₁ = 5 - 3 =2
we know that the sum of nth term of an AP
sₙ = n/2 { 2a + (n - 1 ) d}
putting the value of given term.
sₙ = n/2 { 2 * 3 + ( n - 1 ) 2
sₙ = n ( 3 + ( n - 1 )
sₙ = 3n + n² - n
sn = n² + 2n Answer
__________________________________
Hope it helps you !!!
@Rajukumar111
nth term of an A.P is (2n+ 1 )
Hence,
a₁ =2 * 1 + 1
a₁= 3
similarly ,
a₂ = 2* 2 + 1
a₂= 5
∵ d = a₂ - a₁ = 5 - 3 =2
we know that the sum of nth term of an AP
sₙ = n/2 { 2a + (n - 1 ) d}
putting the value of given term.
sₙ = n/2 { 2 * 3 + ( n - 1 ) 2
sₙ = n ( 3 + ( n - 1 )
sₙ = 3n + n² - n
sn = n² + 2n Answer
__________________________________
Hope it helps you !!!
@Rajukumar111
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