Category: Permutation and Combination

Question Number 148092 by puissant last updated on 25/Jul/21 Answered by Olaf_Thorendsen last updated on 25/Jul/21 $$\mathrm{R}\mathrm{est}\mathrm{le}\mathrm{rayon}\mathrm{du}\mathrm{cercle}.$$$$\mathrm{O}\mathrm{est}\mathrm{le}\mathrm{centre}\mathrm{du}\mathrm{cercle}.$$$$\mathrm{B}\left(\begin{array}{c}\mathrm{R}\\ \mathrm{R}\end{array}\right),\mathrm{C}\left(\begin{array}{c}\mathrm{R}\\ \mathrm{R}-15\end{array}\right)$$$$\mathrm{Aire}_{\mathrm{ABC}} \:=\:\frac{\mathrm{1}}{\mathrm{2}}\mathrm{AB}×\mathrm{AC} \…

Question Number 16868 by tawa tawa last updated on 27/Jun/17 $$\mathrm{In}\mathrm{how}\mathrm{many}\mathrm{ways}\mathrm{can}\mathrm{the}\mathrm{letters}\mathrm{of}\mathrm{the}\mathrm{word}.\mathrm{EVERMORE}\mathrm{be}\mathrm{arrange}$$$$\mathrm{if}\mathrm{the}\mathrm{word}\mathrm{must}\mathrm{begin}\mathrm{with}$$$$\left(\mathrm{i}\right)\mathrm{R}$$$$\left(\mathrm{ii}\right)\mathrm{E}$$ Answered by mrW1 last updated on…

Question Number 16836 by tawa tawa last updated on 26/Jun/17 $$\mathrm{Find}\mathrm{how}\mathrm{many}\mathrm{number}\mathrm{greater}\mathrm{than}2,500\mathrm{can}\mathrm{be}\mathrm{formed}\mathrm{from}\mathrm{the}\mathrm{digit}$$$$0,1,2,3,4\mathrm{if}\mathrm{no}\mathrm{digit}\mathrm{can}\mathrm{be}\mathrm{used}\mathrm{more}\mathrm{than}\mathrm{once}.$$ Answered by mrW1 last updated on 27/Jun/17 $$2\times 4\times 3\times 2=48$$…

Question Number 147654 by ArielVyny last updated on 22/Jul/21 Commented by ArielVyny last updated on 22/Jul/21 $$exercice11$$ Terms of Service Privacy Policy Contact:…

Question Number 146824 by alcohol last updated on 16/Jul/21 Answered by Olaf_Thorendsen last updated on 16/Jul/21 $$1-$$$$w=e^{\frac{2i\pi }{n}}$$$$\mathrm{Let}{z}_n=1+w+w^2+\dots w^{n-1}$$$${z}_{{n}}…