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7.Binomial Theorem
normal
જો વિસ્તરણ ${\left[ {{a^{\frac{1}{{13}}}}\,\, + \,\,\frac{a}{{\sqrt {{a^{ - 1}}} }}} \right]^n}$ નું બીજું પદ $14a^{5/2}$ હોય તો $\frac{{^n{C_3}}}{{^n{C_2}}}$ ની કિમત મેળવો
A
$4$
B
$3$
C
$12$
D
$6$
Solution
$T_{2}={ }^{n} C_{1}\left(a^{1 / 13}\right)^{n-1} \cdot a \sqrt{a}=14 a^{5 / 2}$
$\Rightarrow n-1$
$\frac{n-1}{13}=14 a$
$\Rightarrow \frac{n-1}{13}=14$
$\Rightarrow \frac{n-14}{13}=0$
$\Rightarrow n=14$
$\frac{14}{14} C_{2}=\frac{14 !}{3 ! 1 !} \frac{2 ! 2 !}{14 !}=\frac{12}{3}=4$
Standard 11
Mathematics
