${\sum\limits_{r = 1}^{19} {\frac{{{}^{20}{C_{r + 1}}\left( { - 1} \right)}}{{{2^{2r + 1}}}}} ^r}$ ની કિમત મેળવો
$2\left( {{{\left( {\frac{3}{4}} \right)}^{20}} + 4} \right)$
$-2\left( {{{\left( {\frac{3}{4}} \right)}^{20}} + 4} \right)$
$2\left( {{{\left( {\frac{3}{4}} \right)}^{20}} - 4} \right)$
$-2\left( {{{\left( {\frac{3}{4}} \right)}^{20}} - 4} \right)$
જો ${s_1} = \mathop \sum \limits_{j = 1}^{10} j\left( {j - 1} \right)\left( {\begin{array}{*{20}{c}}{10}\\j\end{array}} \right)\;,$$\;{s_2} = \mathop \sum \limits_{j = 1}^{10} j\;\left( {\begin{array}{*{20}{c}}{10}\\j\end{array}} \right)\;and,$${s_3} = \mathop \sum \limits_{j = 1}^{10} {j^2}\left( {\begin{array}{*{20}{c}}{10}\\j\end{array}} \right)\;,\;$
વિધાન $1$:${s_3} = 55 \times {2^9}$
વિધાન $2$: ${s_1} = 90 \times {2^8}\;$અને ${s_2} = 10 \times {2^8}$
શ્રેણી $aC_0 + (a + b)C_1 + (a + 2b)C_2 + ..... + (a + nb)C_n$ નો સરવાળો મેળવો
જ્યાં $Cr's$ એ $(1 + x)^n, n \in N$ ના વિસ્તરણમાં સહગુણક દર્શાવે છે
$^{15}C_0^2{ - ^{15}}C_1^2{ + ^{15}}C_2^2 - ....{ - ^{15}}C_{15}^2$ = . . .
$\frac{1}{1 ! 50 !}+\frac{1}{3 ! 48 !}+\frac{1}{5 ! 46 !}+\ldots .+\frac{1}{49 ! 2 !}+\frac{1}{51 ! 1 !}$ ની કિમંત મેળવો.
$\left( {\begin{array}{*{20}{c}}n\\0\end{array}} \right) + 2\,\left( {\begin{array}{*{20}{c}}n\\1\end{array}} \right) + {2^2}\left( {\begin{array}{*{20}{c}}n\\2\end{array}} \right) + ..... + {2^n}\left( {\begin{array}{*{20}{c}}n\\n\end{array}} \right)=$ . . .