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If nth term of an AP is 5-2n. what is the sum of n termt?? |
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Answer» n=1 5-2*1=3Similarly whenn=25-2*2=1n=35-2*3=-1 and so on...........This forms an AP =3,1,-1a=3 & d=-2 Sn =n/2[3+5-2n]=n/2[8-2n]=n/2*2(4-n)=n(4-n) N1=5-2(1)=3 ;n2 =5-2(2)=4 a=3;d=4-3 =1 sn=n/2(2a(n-1)d |
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