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Category: Set Theory

Question-12291

Question Number 12291 by 1kanika# last updated on 18/Apr/17 Answered by 433 last updated on 07/May/17 $$\begin{bmatrix}{\mathrm{0}}&{\mathrm{1}}\\{\mathrm{1}}&{\mathrm{0}}\end{bmatrix}×\begin{bmatrix}{\mathrm{0}}&{−\mathrm{1}}\\{\mathrm{1}}&{\mathrm{0}}\end{bmatrix}=\begin{bmatrix}{\mathrm{1}}&{\mathrm{0}}\\{\mathrm{0}}&{−\mathrm{1}}\end{bmatrix}={A} \\ $$$$\begin{bmatrix}{\mathrm{0}}&{−\mathrm{1}}\\{\mathrm{1}}&{\mathrm{0}}\end{bmatrix}×\begin{bmatrix}{\mathrm{0}}&{\mathrm{1}}\\{\mathrm{1}}&{\mathrm{0}}\end{bmatrix}=\begin{bmatrix}{−\mathrm{1}}&{\mathrm{0}}\\{\mathrm{0}}&{\mathrm{1}}\end{bmatrix}=−{A} \\ $$$$\begin{bmatrix}{\mathrm{0}}&{−\mathrm{1}}\\{\mathrm{1}}&{\mathrm{0}}\end{bmatrix}×\begin{bmatrix}{\mathrm{0}}&{−\mathrm{1}}\\{\mathrm{1}}&{\mathrm{0}}\end{bmatrix}=\begin{bmatrix}{−\mathrm{1}}&{\mathrm{0}}\\{\mathrm{0}}&{−\mathrm{1}}\end{bmatrix}=−{I}_{\mathrm{2}} \\ $$$$\begin{bmatrix}{\mathrm{0}}&{\mathrm{1}}\\{\mathrm{1}}&{\mathrm{0}}\end{bmatrix}^{\mathrm{2}} ={I}_{\mathrm{2}} \\…

Master-comes-after-Chess-disappeared-Boyka-comes-after-Master-disappeared-BK-comes-after-Boyka-disappeared-What-comes-after-BK-disappeared-1-A-Team-2-Girlka-3-Bezirksschornsteinfegermeister-

Question Number 77746 by mr W last updated on 09/Jan/20 $${Master}\:{comes}\:{after}\:{Chess}\:{disappeared}. \\ $$$${Boyka}\:{comes}\:{after}\:{Master}\:{disappeared}. \\ $$$${BK}\:{comes}\:{after}\:{Boyka}\:{disappeared}. \\ $$$${What}\:{comes}\:{after}\:{BK}\:{disappeared}? \\ $$$$\mathrm{1}.\:\:{A}−{Team} \\ $$$$\mathrm{2}.\:\:{Girlka} \\ $$$$\mathrm{3}.\:\:{Bezirksschornsteinfegermeister} \\ $$$$\mathrm{4}.\:\:{none}\:{from}\:{above}…

An-analyst-was-hired-to-survey-20-students-He-reported-that-6-eat-eba-5-eat-amala-and-7-eat-semovita-9-eat-eba-or-amala-12-amala-or-semovita-and-9-eba-or-semovita-3-eat-all-the-three-food-and-10-

Question Number 10000 by Tawakalitu ayo mi last updated on 20/Jan/17 $$\mathrm{An}\:\mathrm{analyst}\:\mathrm{was}\:\mathrm{hired}\:\mathrm{to}\:\mathrm{survey}\:\mathrm{20}\:\mathrm{students}. \\ $$$$\mathrm{He}\:\mathrm{reported}\:\mathrm{that}\:\mathrm{6}\:\mathrm{eat}\:\mathrm{eba},\:\mathrm{5}\:\mathrm{eat}\:\mathrm{amala}\:\mathrm{and} \\ $$$$\mathrm{7}\:\mathrm{eat}\:\mathrm{semovita}.\:\mathrm{9}\:\mathrm{eat}\:\mathrm{eba}\:\mathrm{or}\:\mathrm{amala},\:\mathrm{12}\:\mathrm{amala} \\ $$$$\mathrm{or}\:\mathrm{semovita}\:\mathrm{and}\:\mathrm{9}\:\mathrm{eba}\:\mathrm{or}\:\mathrm{semovita}.\:\mathrm{3}\:\mathrm{eat}\:\mathrm{all} \\ $$$$\mathrm{the}\:\mathrm{three}\:\mathrm{food}\:\mathrm{and}\:\mathrm{10}\:\mathrm{eat}\:\mathrm{none}.\:\mathrm{After}\:\mathrm{a}\:\mathrm{careful} \\ $$$$\mathrm{analysis}\:\mathrm{of}\:\mathrm{these}\:\mathrm{findings},\:\mathrm{the}\:\mathrm{analyst}\:\mathrm{was}\:\mathrm{fired}. \\ $$$$\mathrm{why}\:??? \\…

if-x-and-y-are-two-sets-such-that-n-x-17-n-y-23-and-n-X-Y-38-find-n-X-Y-

Question Number 9423 by Rohit kumar last updated on 08/Dec/16 $${if}\:{x}\:{and}\:{y}\:{are}\:{two}\:{sets}\:{such}\:{that}\:{n}\left({x}\right) \\ $$$$=\mathrm{17}\:,\:{n}\left({y}\right)=\mathrm{23}\:{and}\:{n}\left({X}\cup{Y}\right)\:=\mathrm{38}, \\ $$$$\boldsymbol{{find}}\:\boldsymbol{{n}}\left({X}\cup{Y}\right). \\ $$ Commented by sandy_suhendra last updated on 08/Dec/16 $$\mathrm{do}\:\mathrm{you}\:\mathrm{mean}\:\mathrm{n}\left(\mathrm{X}\cap\mathrm{Y}\right)\:?…

Question-74590

Question Number 74590 by Aditya789 last updated on 27/Nov/19 Answered by MJS last updated on 27/Nov/19 $${n}=\mathrm{7} \\ $$$$\mathrm{the}\:\mathrm{coefficients}\:\mathrm{then}\:\mathrm{are}\:\begin{pmatrix}{{n}}\\{{k}}\end{pmatrix}\:\mathrm{with}\:{n}=\mathrm{7};\:\mathrm{0}\leqslant{k}\leqslant\mathrm{7} \\ $$$$\begin{pmatrix}{\mathrm{7}}\\{\mathrm{0}}\end{pmatrix};\:\begin{pmatrix}{\mathrm{7}}\\{\mathrm{1}}\end{pmatrix};\:\begin{pmatrix}{\mathrm{7}}\\{\mathrm{2}}\end{pmatrix};\:\begin{pmatrix}{\mathrm{7}}\\{\mathrm{3}}\end{pmatrix};\:\begin{pmatrix}{\mathrm{7}}\\{\mathrm{4}}\end{pmatrix};\:\begin{pmatrix}{\mathrm{7}}\\{\mathrm{5}}\end{pmatrix};\:\begin{pmatrix}{\mathrm{7}}\\{\mathrm{6}}\end{pmatrix};\:\begin{pmatrix}{\mathrm{7}}\\{\mathrm{7}}\end{pmatrix} \\ $$$$\mathrm{1}\:\mathrm{7}\:\mathrm{21}\:\mathrm{35}\:\mathrm{35}\:\mathrm{21}\:\mathrm{7}\:\mathrm{1} \\ $$…

Prove-that-If-A-B-and-C-are-subset-of-the-same-universal-set-then-A-B-A-C-A-B-C-

Question Number 7440 by Tawakalitu. last updated on 29/Aug/16 $${Prove}\:{that} \\ $$$${If}\:\:{A},\:{B}\:{and}\:{C}\:{are}\:{subset}\:{of}\:{the}\:{same}\:{universal}\:{set} \\ $$$${then}\:\left({A}\:−\:{B}\right)\:\cap\:\left({A}\:−\:{C}\right)\:=\:{A}\:−\:\left({B}\:−\:{C}\right) \\ $$ Commented by Yozzia last updated on 29/Aug/16 $${Let}\:{A}=\left\{\mathrm{1},\mathrm{2},\mathrm{3},\mathrm{4}\right\},\:{B}=\left\{\mathrm{2},\mathrm{3},\mathrm{4},\mathrm{5}\right\},\:{C}=\left\{\mathrm{3},\mathrm{4},\mathrm{5},\mathrm{6}\right\}. \\…