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8. Sequences and Series
easy
જો $\text{a}$ અને $\text{b}$ નો સમાંતર મધ્યક $\frac{{{a}^{n+1}}+{{b}^{n+1}}}{{{a}^{n}}\,+\,{{b}^{n}}}$ હોય,તો $\,\text{n =}.......$
A
$1$
B
$-1$
C
$0$
D
આપેલ પૈકી એક પણ નહિ
Solution
$\frac{{{a}^{n\,+\,1}}\,+\,{{b}^{n\,+\,1}}}{{{a}^{n}}\,+\,\,{{b}^{n}}}\,\,=\,\,\frac{a\,\,+\,\,b}{2}$
$\Rightarrow \,\,{{a}^{n\,+\,1}}\,-\,\,a{{b}^{n}}\,+\,\,{{b}^{n\,+\,1}}\,-\,\,b{{a}^{n}}\,=\,\,0\,\,$
$\Rightarrow \,\,(a\,\,-\,\,b)\,\,({{a}^{n}}\,-\,\,{{b}^{n}})\,\,=\,\,0$
જો $\,{{a}^{n}}\,-\,\,{{b}^{n}}\,=\,\,0\,$ હોય, તો ${{\left( \frac{\text{a}}{\text{b}} \right)}^{n}}\,=\,\,1\,\,=\,\,{{\left( \frac{a}{b} \right)}^{0}}\,\,$
$\Rightarrow \,\,n\,\,=\,\,0$
Standard 11
Mathematics