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let-n-be-a-fixed-positive-integer-How-many-ways-are-there-to-write-n-as-a-sum-of-positive-integers-n-a-1-a-2-a-k-with-k-arbitary-positive-integer-and-a-1-a-2-a-k-a-1-1-for-example-wi

Question Number 26513 by gunawan last updated on 26/Dec/17 $$\mathrm{let}\:{n}\:\mathrm{be}\:\mathrm{a}\:\mathrm{fixed}\:\mathrm{positive}\:\mathrm{integer}.\:\mathrm{How}\:\mathrm{many}\:\mathrm{ways}\:\mathrm{are}\:\mathrm{there}\:\mathrm{to}\:\mathrm{write}\:{n}\:\mathrm{as}\:\mathrm{a}\:\mathrm{sum}\:\mathrm{of} \\ $$$$\mathrm{positive}\:\mathrm{integers},\: \\ $$$${n}={a}_{\mathrm{1}} +{a}_{\mathrm{2}} +…+{a}_{{k}} \\ $$$$\mathrm{with}\:{k}\:\mathrm{arbitary}\:\mathrm{positive}\:\mathrm{integer}\:\mathrm{and}\:{a}_{\mathrm{1}} \leqslant{a}_{\mathrm{2}} …\leqslant{a}_{{k}} \leqslant{a}_{\mathrm{1}} +\mathrm{1}.\:\mathrm{for}\:\mathrm{example} \\ $$$$\mathrm{with}\:{n}=\mathrm{4},\:\mathrm{there}\:\mathrm{are}\:\mathrm{four}\:\mathrm{ways}\::\:\mathrm{4},\:\mathrm{2}+\mathrm{2},\:\mathrm{1}+\mathrm{1}+\mathrm{2},\mathrm{1}+\mathrm{1}+\mathrm{1}+\mathrm{1} \\…

x-1-x-2-x-1-dx-

Question Number 92025 by 675480065 last updated on 04/May/20 $$\int\left(\frac{\mathrm{x}−\mathrm{1}}{\mathrm{x}^{\mathrm{2}} −\mathrm{x}−\mathrm{1}}\right)\mathrm{dx} \\ $$ Commented by mathmax by abdo last updated on 04/May/20 $${I}\:=\int\:\frac{{x}−\mathrm{1}}{{x}^{\mathrm{2}} −{x}−\mathrm{1}}{dx}\:\Rightarrow\:{I}\:=\frac{\mathrm{1}}{\mathrm{2}}\int\frac{\mathrm{2}{x}−\mathrm{1}−\mathrm{1}}{{x}^{\mathrm{2}} −{x}−\mathrm{1}}{dx}…

A-body-is-projected-vertically-upward-with-an-initial-velocity-of-u-Another-Another-body-is-projected-with-the-same-initial-velocity-t-seconds-after-the-first-If-T-is-the-time-when-the-two-bodies-

Question Number 26425 by tawa tawa last updated on 25/Dec/17 $$\mathrm{A}\:\mathrm{body}\:\mathrm{is}\:\mathrm{projected}\:\mathrm{vertically}\:\mathrm{upward}\:\mathrm{with}\:\mathrm{an}\:\mathrm{initial}\:\mathrm{velocity}\:\mathrm{of}\:\mathrm{u}.\:\mathrm{Another} \\ $$$$\mathrm{Another}\:\mathrm{body}\:\mathrm{is}\:\mathrm{projected}\:\mathrm{with}\:\mathrm{the}\:\mathrm{same}\:\mathrm{initial}\:\mathrm{velocity},\:\mathrm{t}\:\mathrm{seconds}\:\mathrm{after} \\ $$$$\mathrm{the}\:\mathrm{first}.\:\mathrm{If}\:\:\mathrm{T}\:\mathrm{is}\:\mathrm{the}\:\mathrm{time}\:\mathrm{when}\:\mathrm{the}\:\mathrm{two}\:\mathrm{bodies}\:\mathrm{meet},\:\mathrm{and}\:\mathrm{g}\:\mathrm{the}\:\mathrm{acceleration} \\ $$$$\mathrm{due}\:\mathrm{to}\:\mathrm{gravity},\:\mathrm{Show}\:\mathrm{that}\:\:\:\boldsymbol{\mathrm{T}}\:=\:\frac{\mathrm{2u}\:+\:\mathrm{gt}}{\mathrm{2g}} \\ $$ Terms of Service Privacy Policy Contact:…

The-front-of-a-train-80m-long-passes-a-signal-at-a-speed-of-72km-hr-If-the-rear-of-the-train-passes-the-signal-5s-later-Find-a-The-magnitude-of-the-acceleration-of-the-train-b-The-speed-at-whic

Question Number 26424 by tawa tawa last updated on 25/Dec/17 $$\mathrm{The}\:\mathrm{front}\:\mathrm{of}\:\mathrm{a}\:\mathrm{train}\:\mathrm{80m}\:\mathrm{long}\:\mathrm{passes}\:\mathrm{a}\:\mathrm{signal}\:\mathrm{at}\:\mathrm{a}\:\mathrm{speed}\:\mathrm{of}\:\mathrm{72km}/\mathrm{hr}.\:\mathrm{If}\:\mathrm{the} \\ $$$$\mathrm{rear}\:\mathrm{of}\:\mathrm{the}\:\mathrm{train}\:\mathrm{passes}\:\mathrm{the}\:\mathrm{signal}\:\mathrm{5s}\:\mathrm{later},\:\mathrm{Find} \\ $$$$\left(\mathrm{a}\right)\:\mathrm{The}\:\mathrm{magnitude}\:\mathrm{of}\:\mathrm{the}\:\mathrm{acceleration}\:\mathrm{of}\:\mathrm{the}\:\mathrm{train}. \\ $$$$\left(\mathrm{b}\right)\:\mathrm{The}\:\mathrm{speed}\:\mathrm{at}\:\mathrm{which}\:\mathrm{the}\:\mathrm{rear}\:\mathrm{of}\:\mathrm{the}\:\mathrm{train}\:\mathrm{passes}\:\mathrm{the}\:\mathrm{signal}. \\ $$ Terms of Service Privacy Policy Contact:…