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1.Relation and Function
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જો $f(x)$ એ બહુપદી વિધેય હોય કે જેથી $f(x).f (\frac{1}{x}) = f(x) + f (\frac{1}{x})$ અને $f(4) = 65$ થાય તો $f(6)$ ની કિમત મેળવો.
A
$217$
B
$215$
C
$216$
D
$65$
Solution
$\because \mathrm{f}(\mathrm{x}) \cdot \mathrm{f}(1 / \mathrm{x})=\mathrm{f}(\mathrm{x})+\mathrm{f}(1 / \mathrm{x})$
$\therefore {\rm{f}}({\rm{x}}) = 1 \pm {{\rm{x}}^{\rm{n}}}\left( {{\rm{i}}{{\rm{n}}^{**}}{\rm{ star\,\, point }}} \right)$
$f(4)=65 \therefore f(x)=x^{3}+1$
$f(6)=6^{3}+1=217.$
Standard 12
Mathematics