A) \[\frac{2}{n}-\frac{1}{{{n}^{2}}}\]
B) \[\frac{1}{{{n}^{2}}}-\frac{1}{n}\]
C) \[\frac{2}{{{n}^{2}}}-\frac{1}{n}\]
D) \[\frac{2}{n}-\frac{1}{{{n}^{2}}}\]
Correct Answer: A
Solution :
We know, \[{{s}_{n}}=u+\frac{a}{2}(2n-1)=0+\frac{a}{2}(2n-1)\] Again, \[s=ut+\frac{1}{z}a{{t}^{2}}\] \[=0+\frac{1}{2}a{{n}^{2}}\] \[[\because \,\,t=n\sec ]\] \[\therefore \] \[\frac{{{s}_{n}}}{s}=\frac{\frac{a}{2}(2n-1)}{a{{n}^{2}}/2}=\frac{2}{n}-\frac{1}{{{n}^{2}}}\]You need to login to perform this action.
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