If a is the first term of an infinite GP with sum equal to 5 , then

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Professor PC Thomas Classes · Answer

If r is the C r. of the infinite GP , then $ \frac{\mathrm{a}}{1-\mathrm{r}}=5, \mathrm{r}=\frac{5-\mathrm{a}}{5} $ \  Since \  $|\mathrm{r}|<1$, $ \begin{aligned} & -1<\frac{5-a}{5}<1 \ & -5<5-a<5 \ & -10<-a<0,0<a<10 \end{aligned} $