Question Number 163263 by Ar Brandon last updated on 05/Jan/22 Answered by qaz last updated on 05/Jan/22 $$\underset{\mathrm{k}=\mathrm{1}} {\overset{\mathrm{n}} {\sum}}\left(−\mathrm{1}\right)^{\mathrm{k}} \mathrm{k}\begin{pmatrix}{\mathrm{n}}\\{\mathrm{k}}\end{pmatrix}=\frac{\partial}{\partial\mathrm{x}}\mid_{\mathrm{x}=\mathrm{1}} \left(\underset{\mathrm{k}=\mathrm{0}} {\overset{\mathrm{n}} {\sum}}\begin{pmatrix}{\mathrm{n}}\\{\mathrm{k}}\end{pmatrix}\left(−\mathrm{x}\right)^{\mathrm{k}} −\mathrm{1}\right)=\frac{\partial}{\partial\mathrm{x}}\mid_{\mathrm{x}=\mathrm{1}}…
Question Number 32093 by NECx last updated on 19/Mar/18 $${Find}\:{the}\:{number}\:{of}\:{ways}\:{of} \\ $$$${selecting}\:\mathrm{9}\:{balls}\:{from}\:\mathrm{6}\:{red}\:{balls}, \\ $$$$\mathrm{5}\:{white}\:{balls}\:{and}\:\mathrm{5}\:{blue}\:{balls}\:{if} \\ $$$${each}\:{selection}\:{consists}\:{of}\:\mathrm{3}\:{balls} \\ $$$${of}\:{each}\:{colour}. \\ $$ Answered by Joel578 last updated…
Question Number 97600 by Power last updated on 08/Jun/20 Answered by mahdi last updated on 08/Jun/20 $$\mathrm{19}\:\mathrm{trangles} \\ $$$$\mathrm{3},\mathrm{4},\mathrm{5}\:\&\:\mathrm{3},\mathrm{4},\mathrm{6}\:\&\:\mathrm{4},\mathrm{5},\mathrm{6}\:\&\:\mathrm{3},\mathrm{5},\mathrm{6} \\ $$$$\mathrm{3},\mathrm{3},\mathrm{4}\:\&\:\mathrm{3},\mathrm{3},\mathrm{5}\:\&\:\mathrm{4},\mathrm{4},\mathrm{3}\:\&\:\mathrm{4},\mathrm{4},\mathrm{5}\:\&\:\mathrm{4},\mathrm{4},\mathrm{6} \\ $$$$\mathrm{5},\mathrm{5},\mathrm{3}\:\&\:\mathrm{5},\mathrm{5},\mathrm{4}\:\&\:\mathrm{5},\mathrm{5},\mathrm{6}\:\&\:\mathrm{6},\mathrm{6},\mathrm{3}\:\&\:\mathrm{6},\mathrm{6},\mathrm{4}\:\&\:\mathrm{6},\mathrm{6},\mathrm{5} \\ $$$$\mathrm{3},\mathrm{3},\mathrm{3}\:\&\:\mathrm{4},\mathrm{4},\mathrm{4}\:\&\:\mathrm{5},\mathrm{5},\mathrm{5}\:\&\:\mathrm{6},\mathrm{6},\mathrm{6}…
Question Number 97492 by 675480065 last updated on 08/Jun/20 Answered by smridha last updated on 08/Jun/20 $$\boldsymbol{{let}}\:\boldsymbol{{ln}}\left(\boldsymbol{{x}}\right)=−\boldsymbol{{k}}\:\boldsymbol{{so}}\:\boldsymbol{{we}}\:\boldsymbol{{get}} \\ $$$$\int_{\mathrm{0}} ^{\infty} \boldsymbol{{e}}^{−\mathrm{2021}\boldsymbol{{k}}} \boldsymbol{{k}}^{\mathrm{2020}} \boldsymbol{{dk}} \\ $$$$=\frac{\boldsymbol{\Gamma}\left(\mathrm{2021}\right)}{\left(\mathrm{2021}\right)^{\mathrm{2021}}…
Question Number 31714 by gunawan last updated on 13/Mar/18 $$\mathrm{Prove}\:\mathrm{that} \\ $$$$\underset{\mathrm{1}} {\overset{{n}−\mathrm{2}} {\sum}}{k}\begin{pmatrix}{\:{n}−\mathrm{2}}\\{\:\:{k}}\end{pmatrix}\begin{pmatrix}{{n}+\mathrm{2}}\\{{k}+\mathrm{2}}\end{pmatrix}\:=\:\left({n}−\mathrm{2}\right)\begin{pmatrix}{\mathrm{2}{n}−\mathrm{1}}\\{{n}−\mathrm{1}}\end{pmatrix} \\ $$ Terms of Service Privacy Policy Contact: info@tinkutara.com
Question Number 31713 by gunawan last updated on 13/Mar/18 $$\mathrm{Given}\:{n}\:\in\:\mathbb{N} \\ $$$$\mathrm{prove}\:\mathrm{that} \\ $$$$\underset{{k}=\mathrm{1}} {\overset{{n}} {\sum}}{k}\left({n}+\mathrm{1}−{k}\right)=\begin{pmatrix}{\:{n}+\mathrm{2}}\\{\:\:\:\:\:\mathrm{3}}\end{pmatrix} \\ $$ Commented by abdo imad last updated on…
Question Number 97045 by john santu last updated on 06/Jun/20 $$\mathrm{a}\:\mathrm{committee}\:\mathrm{consisting}\:\mathrm{of} \\ $$$$\mathrm{5}\:\mathrm{men}\:\&\:\mathrm{4}\:\mathrm{women}\:\mathrm{is}\:\mathrm{to}\:\mathrm{be}\: \\ $$$$\mathrm{chosen}\:\mathrm{from}\:\mathrm{8}\:\mathrm{men}\:\&\:\mathrm{4}\:\mathrm{women}. \\ $$$$\mathrm{If}\:\mathrm{one}\:\mathrm{man}\:\&\:\mathrm{one}\:\mathrm{woman}\:\mathrm{are}\:\mathrm{husband}\: \\ $$$$\&\:\mathrm{wife}\:,\:\mathrm{how}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{can}\: \\ $$$$\mathrm{the}\:\mathrm{committee}\:\mathrm{be}\:\mathrm{chosen}\:\mathrm{if} \\ $$$$\mathrm{only}\:\mathrm{one}\:\mathrm{of}\:\mathrm{the}\:\mathrm{husband}\:\&\:\mathrm{wife} \\ $$$$\mathrm{must}\:\mathrm{be}\:\mathrm{chosen}\:?…
Question Number 96815 by Ar Brandon last updated on 05/Jun/20 $$\mathrm{In}\:\mathrm{how}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{can}\:\mathrm{3}\:\mathrm{boys}\:\mathrm{and}\:\mathrm{3}\:\mathrm{girls}\:\mathrm{be} \\ $$$$\mathrm{sitted}\:\mathrm{in}\:\mathrm{a}\:\mathrm{line}? \\ $$ Answered by 1549442205 last updated on 05/Jun/20 $$\mathrm{it}\:\mathrm{is}\:\mathrm{too}\:\mathrm{simple}\:\mathrm{6}! \\ $$…
Question Number 96276 by mr W last updated on 31/May/20 Commented by mr W last updated on 31/May/20 $$\mathrm{Repost}\:\mathrm{of}\:\mathrm{an}\:\mathrm{unanswered}\:\mathrm{question} \\ $$$$\left({Q}\mathrm{88876}\right) \\ $$ Commented by…
Question Number 95912 by i jagooll last updated on 28/May/20 $$\begin{pmatrix}{\mathrm{2n}}\\{\mathrm{n}}\end{pmatrix}\:=\:\mathrm{20}\: \\ $$$$\mathrm{find}\:\mathrm{n}? \\ $$ Commented by MJS last updated on 28/May/20 $${n}=\mathrm{3} \\ $$…