If the sum of the first n term of an AP is 4n -n^2, what is the first term ( that is S↓1)? What is the sum of first two terms? What is second term? Similarly, find the 3rd, the 10th and the nth terms?
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IF n=1 Sn=4*1^2=4=1st term(T1)
IF n=2 Sn=4*2^2=16=S2
S2-S1=T2=16-4=12
therefore,d=12-4=8
hence, 3rd term=12+8=20
10th term=a+9d=4+9*8=76
and, nth term=a+(n-1)d=4+(n-1)8=-4+8n....
I hope it helps you
PLEASE MARK BRAINLIEST
IF n=2 Sn=4*2^2=16=S2
S2-S1=T2=16-4=12
therefore,d=12-4=8
hence, 3rd term=12+8=20
10th term=a+9d=4+9*8=76
and, nth term=a+(n-1)d=4+(n-1)8=-4+8n....
I hope it helps you
PLEASE MARK BRAINLIEST
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