Question

If Sn=4n²+n-7n find A.P and n term
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Answer 1

Answer:

sn=3n^2

Step-by-step explanation:

4n^2+n=4n^3

4n^3-7n

3n^2

Answer 2

sn=4n-n2

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2=4(2)-(2)2=8-4=4

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2=4(2)-(2)2=8-4=4second term,a2=S2-S1=4-3=1

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2=4(2)-(2)2=8-4=4second term,a2=S2-S1=4-3=1d=a2-a=1-3=-1

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2=4(2)-(2)2=8-4=4second term,a2=S2-S1=4-3=1d=a2-a=1-3=-1an=a+(n-1)d

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2=4(2)-(2)2=8-4=4second term,a2=S2-S1=4-3=1d=a2-a=1-3=-1an=a+(n-1)d=3+(n-1) (-2)

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2=4(2)-(2)2=8-4=4second term,a2=S2-S1=4-3=1d=a2-a=1-3=-1an=a+(n-1)d=3+(n-1) (-2)=3-2n+2

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2=4(2)-(2)2=8-4=4second term,a2=S2-S1=4-3=1d=a2-a=1-3=-1an=a+(n-1)d=3+(n-1) (-2)=3-2n+2=5-2n

sn=4n-n2first term a=s1=4(1)-(1)-(1)=4-1=3sum of first two terms=S2=4(2)-(2)2=8-4=4second term,a2=S2-S1=4-3=1d=a2-a=1-3=-1an=a+(n-1)d=3+(n-1) (-2)=3-2n+2=5-2na10=5-2(10)=5-20=-15