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Question-57621




Question Number 57621 by Gulay last updated on 08/Apr/19
Commented by Gulay last updated on 08/Apr/19
sir help me plz
$$\mathrm{sir}\:\mathrm{help}\:\mathrm{me}\:\mathrm{plz} \\ $$
Answered by tanmay.chaudhury50@gmail.com last updated on 08/Apr/19
S_9 =(9/2)[2a+(9−1)d]  72=(9/2)×2[a+4d]    ((72)/9)=T_5 →T_5 =8  T_n =a+(n−1)d
$${S}_{\mathrm{9}} =\frac{\mathrm{9}}{\mathrm{2}}\left[\mathrm{2}{a}+\left(\mathrm{9}−\mathrm{1}\right){d}\right] \\ $$$$\mathrm{72}=\frac{\mathrm{9}}{\mathrm{2}}×\mathrm{2}\left[{a}+\mathrm{4}{d}\right] \\ $$$$ \\ $$$$\frac{\mathrm{72}}{\mathrm{9}}={T}_{\mathrm{5}} \rightarrow{T}_{\mathrm{5}} =\mathrm{8} \\ $$$${T}_{{n}} ={a}+\left({n}−\mathrm{1}\right){d} \\ $$

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